group-picture-052018_smaller

SPINTRONICS

RESEARCH

RSS Latest Publications

Spintronics Research Group

Spintronics is a research area trying to take profit from the spin of the electrons as a mean to obtain, transmit and process information. The spin of the electrons is a degree of freedom that is not explored by conventional electronics rely only on the electrical charge to drive electronic circuits. Spintronics use magnetic materials patterned at the nano-scale to produce spin polatized currents which drive a new class of beyond CMOS components which include magnetic field sensors, non-volatile memories and RF devices.

group-picture-052018_smaller

Spintronics research team (picture from April 2018)

TOPICS

MAGNETIC ANNEALING SYSTEM (MATr 2000)

TT00000414_20170321_112923The MATR is a system used for annealing at elevated temperatures (up to 400 °C) in the presence of intense magnetic fields (up to 2 Tesla).  Such magnetic fields are generated by a superconducting magnet module created by running current through windings of this material.  The system can handle multiple wafers of 200mm and 150mm in diameter, in parallel or perpendicular position with respect to the magnetic field. There is also a 1×1 inch sample holder available.

UHV multitarget confocal sputtering tool (Kenosistec)

TT00000886_20151126_125506A multi-target UHV sputtering system consisting of a deposition chamber with 11 2” diameter magnetrons in confocal geometry for the co-deposition of materials, optimized wafers of up to 200m in diameter.

Picture of Timaris FTM - TiW, AlSiCu and Al2O3 sputteringTiW, AlSiCu and Al2O3 sputtering (Timaris FTM)
The Four-Target-Module (FTM) physical vapor deposition cluster tool is especially designed for deposition of high–quality metallic, conductive and insulating films. The system is a UHV single wafer cluster tool and consists of one transport module, one multi-target PVD module with up to four DC/RF cathodes (three targets are install in this machine AlSiCu, TiW and Al2O3) and one soft etch/oxidation module. It is capable of depositing different magnetic and non–magnetic layers on wafers with diameters up to 200mm by DC/RF Magnetron Sputtering, with good uniformity for the deposited films. The FTM incorporates Linear Dynamic Deposition (LDD) technology in combination with up to four sputter targets in one vacuum chamber. The LDD technology enables the capability to deposit wedge films with a different film thickness across the wafer and to deposit alloy films with adjustable concentration gradients across one wafer.

Picture of Timaris MTM - Mutitarget sputtering toolMutitarget sputtering tool (Timaris MTM)
The Multi-Target Module (MTM) physical vapor deposition cluster tool is especially designed for deposition of ultra–thin films, magnetic films, high–quality metallic, conductive and insulating films and multiple film stack deposition comprising these materials without the need to break ultra-high vacuum. The system is a UHV single wafer cluster tool and consists of one transport module, one multi-target PVD module with 10 DC/RF cathodes and one soft etch/oxidation module. It is capable of depositing different magnetic and non–magnetic layers on wafers with diameters up to 200mm by DC/RF Magnetron Sputtering (or Ion Beam Sputtering), with good uniformity for the deposited stacks.
Additional features such as wafer heating for hot substrate deposition or a collinear Aligning Magnetic Field (AMF) are available. The AMF can be activated to align the magnetic easy axis during deposition of ferromagnetic films.
The Linear Dynamic Deposition (LDD) technology enables the capability to deposit wedge films with a different film thickness across the wafer and to deposit alloy films with adjustable concentration gradients across one wafer. Both features allow a very cost effective development of film stacks and accelerate the devices development.

CIPTCurrent in-plane tester (CIPT)
To verify the transport properties of MTJs before nanofabrication a  CIPT is used to perform TMR and RA measurements of bulk MTJ stacks. This is a very useful tool since it allows us to retrieve fundamental information of the MTJ stack prior to fabrication. To perform these measurements, the system contacts 12 cantilever electrodes with a variable spacing, down to 750 nm. It performs electrical measurements (current and voltage) through the different cantilevers with different spacing between them. This allows to determine the RA and TMR. The CIPT can determine RA values down to 0.1 Wμm² and measure the TMR with both in-plane and perpendicular anisotropy with in-plane fields up to 2500 Oe and perpendicular fields up to 1400 Oe.

VSMVibrating Sample Magnetometer (VSM)
The VSM allows the measurement of the magnetic moment as a function of the applied magnetic field of unpatterned samples. Thus, it allowed us to measure and optimize the magnetic stacks and annealings used during this project. The used VSM system can measure magnetic signals down to 5⋅10^-7 emu and very low coercivities (10 mOe; field resolution) and can apply fields up to 2 T. It allows the fast and accurate measurement of the magnetic moment, not only as a function of the applied magnetic field, but also with temperature (which can be swept from 83 to 570 K). Angular and time dependences of the magnetization can be measured as well.

automated_proberAutomatic Transport Measurement Setup
Once the MTJ fabrication process is complete, this setup does a full characterization of thousands of MTJ devices on the full wafer. A system with 40 tips is used to characterized 10 MTJs in a 4-contact scheme per landing site. Statistically meaningful data regarding the device TMR, RA, shape of the transfer curves, and corresponding deviations arising from the nanofabrication process are obtained. Furthermore, a software allows a collecting different figures of merit (TMR, RA, coercive field, linear range of the curve, etc) and organize them for different parameters (die number, pillar sizes, TMR and RA range, etc).

IP_proberRF prober for in-plane magnetic fields
Electrical contact to characterize RF devices was performed using special Cascade Microtech’s probes. These probes allow high accuracy RF measurements with low contact resistance. An optical microscope in conjugation with holders that allow high accuracy movements (both for the sample and the tips) are used to connect the contacts to the device. The RF measurements can be performed while injecting a DC current in the MTJ. Moreover, synchronization and spin diode torque studies can also be performed since an RF signal can be provided to the MTJ and the generated DC voltage measured. The signal is then transported through coaxial cables to a 3 Hz – 44 GHz spectrum analyzer where the emission spectrum can be acquired. Power suppliers are used to provide current both to the MTJ and the magnet. Automated control of the complete system can be performed to make sequences with different values of current and magnetic field. An amplifier is usually used to increase the measured signal, although its use was not necessary in the cases of MTJs with high output power. A bias tee is used to separate the DC and RF electrical components (being the last one sent to the spectrum analyzer). The magnetic field was applied using a small magnet. The orientation of the magnet could be manually changed but it was limited to relatively small magnetic fields (up to 200 Oe) in the in-plane direction.

OOP_proberRF prober for out-of-plane magnetic fields
A similar to the IP measurement setup this is an RF measurement setup with power supplies and spectrum analyzer, but for out-of-plane magnetic fields. Magnetic fields up to 1.6 T can be applied. The magnetic can be rotated between in-plane and out-of-plane direction with a highly precise stepper motor. The applied magnetic field value can be measured directly using a gaussmeter. The setup requires the positioning of the tips with the aid of an optical microscope. After the tips are properly connected to the contacts the microscope is easily displaced and the magnet positioned in the sample position.

SpinAge FETopen

Project Time Frame: 1 October 2020 to 30 September 2024

Weighted Spintronic-Nano-Oscillator-based Neuromorphic Computing System Assisted by laser for Cognitive Computing

Spinning towards a brain-like computer more powerful than any to date

Throughout history, humankind has devoted significant effort to developing machines and tools that can mimic human functions, either relieving people of some of their hard work or surpassing their ability to do it in time or scale. One of the great frontiers is the development of computers that can mimic the human brain in things such as computational power, learning and energy efficiency. The term ‘neuromorphic computing’ was coined more than 30 years ago, and neuromorphic devices are an attempt to mimic aspects of the brain’s architecture and dynamics to achieve these goals. The EU-funded SpinAge project is developing a novel neuromorphic computing system harnessing cutting-edge technologies that could enable an improvement in performance over current systems by at least 4 orders of magnitude, bringing us closer than we have ever been to mimicking the brain with a computer.

RadioSpin FETopen

Project Time Frame: 1 January 2021 to 28 February 2025

Deep Oscillatory Neural Networks Computing and Learning through the Dynamics of RF Neurons Interconnected by RF Spintronic Synapses

The goal of RadioSpin is to build a hardware neural network that computes using neural dynamics as in the brain, has a deep layered architecture as in the neocortex, but runs and learns faster, by seven orders of magnitude. For this purpose, we will use ultrafast radio-frequency (RF) oscillators to imitate the rich, reconfigurable dynamics of biological neurons. Within the RadioSpin project, we will develop a new breed of nanosynapses, based on spintronics technology, that directly process the RF signals sent by neurons and interconnects them layer-wise. We will demonstrate and benchmark our concept by building a lab-scale prototype that co-integrates for the first time CMOS RF neurons with spintronic RF synapses. We will develop brain-inspired algorithms harnessing oscillations, synchrony and edge-of-chaos for computing and show that they can run on RadioSpin deep network RF technology. Finally, we will benchmark RadioSpin technology for biomedical and RF fingerprinting applications where fast and low energy consumption classification of RF signals are key.
To achieve its ambitious goals RadioSpin brings together frontier researchers along the entire chain of neuromorphic engineering, from material science (spintronic nanodevices), physics (non-linear dynamics), electronics (RF CMOS design), computer science (artificial intelligence algorithms), and microwave signal processing. Two innovative companies bring real-life use-cases (microwave mammography and IoT RF fingerprinting). The scientific experts are further complemented by experts in the field of innovation, commercial deployment and IP monetisation, as well as communication and public engagement.

EU comission logo_ce-en-rvb-lr

SPINAR PADR

Project Time Frame: 1 October 2020 to 31 September 2022

Spin-based hardware artificial neural
network for embedded RF processing

Combination of AI and nanotechnology to process radio frequency signals (from radar) to identify the emitter of the signal with very low power consumption and very high efficiency. In SPINAR, an artificial neural network will be implemented directly in hardware, with spin-based nanodevices as neurons and synapses.

INFANTE
Project Time Frame: Nov 2017 to Sep 2020
INFANTE is a development and demonstration project for an in-orbit microsatellite, to be launched in 2020. This is the precursor of a constellation for Earth observation and communication with the focus on maritime applications.
INFANTE will be the first satellite developed by the Portuguese Industry, articulated in a national consortium led by TEKEVER group, that includes 9 companies with references in the space sector, as Active Space Technologies, Omnidea, Active Aerogels, GMV, HPS and Spinworks; and 10 internationally recognized R&D Centers in their areas of competence, such as CEIIA; FEUP, ISQ, FCT-UNL, INL, IPN, IPTomar, ISR Lisbon, IT Aveiro, and UBI.

PRODUTECH-SIF
Project Time Frame: Nov 2017 to Sep 2020
The project embodies a comprehensive response towards the development and implementation of new production systems, embedding advanced production technologies that will equip the manufacturing industry to meet the challenges and opportunities of the 4th industrial revolution.

p2020MAGLINE
Project Time Frame: Apr 2017 to Jan 2020
MAGLINE: Desenvolvimento e Validação Industrial do Processo de Fabricação de Sensores TMR
The latest generation of sensors (TMR) has major advantages over previous (Hall and GMR), and there is a market with sustained growth for application of these sensors. However the lack of industrial production capacity prevents its adoption in large scale commercial applications, although it is possible to acquire them commercially those marketed generic sensors are not optimized for any particular application. There is a clear opportunity to capture this market, and provide the market a large-scale production solution TMR sensors optimized and custom-made for different applications.

MOSAIC
Project Time Frame: Jan 2013 to Sep 2016
The broader objective is to bring the device level knowledge acquired in the past years by the partners towards systems as a first crucial step towards industrialization, warranting the leading position not only of European research but also of European industry in microwave spintronics.

SPINICUR webpage
Project Time Frame: Oct. 2012- Mar. 2016
SPINICUR (from spin currents) is a training network of European experts dedicated to providing state-of-the-art education and training for early stage and experienced researchers. We have concentrated on an aspect of spintronics – pure spin currents – and specific technical goals in order to secure a very high level of industrial involvement and strong network connectivity through a sharp focus.

SpinCal webpage
Project Time Frame: Jul. 2013 – Jun. 2016
SpinCal stands for Spintronics and spin-caloritronics in magnetic nanosystems, a joint research project (JRP) funded by the European Metrology Research Programme (EMRP). The aim of the project is to enable fundamental understanding of new effects emerging in the field of spintronics and spin-caloritronics in magnetic nanosystems. This goal was achieved by developing a new measurement infrastructure and a best practice guide for spin-caloritronic material measurements, providing a road map towards future standardisation of spintronic and spin-caloritronic measurements, materials and devices.

INTEGRATION
Project Time Frame: 2012-2015
Towards hybrid integrated heterogeneous technology devices.

PERPENDICULAR (PTDC-CTM-MET-118236-2010) webpage
Project Time Frame: Jul. 2012- Jun. 2014
Advanced MRAM Structures using Perpendicular Magnetization Materials for Spin Transfer Writing.

PUBLICATIONS

  • 2021

    Iranmehr, Ensieh ; Ferreira, Ricardo ; Bohnert, Tim ; Freitas, Paulo

    Developing a Data-Driven Unsupervised Pattern Recognition Approach for Sensor Signal Anomaly Detection Miscellaneous

    TechRxiv, 2021.

    Links | BibTeX

    Wittrock, Steffen; Talatchian, Philippe; Romera, Miguel; Menshawy, Samh; Garcia, Mafalda Jotta; Cyrille, Marie-Claire; Ferreira, Ricardo; Lebrun, Romain; Bortolotti, Paolo; Ebels, Ursula; Grollier, Julie; Cros, Vincent

    Beyond the gyrotropic motion: Dynamic C-state in vortex spin torque oscillators Journal Article

    Applied Physics Letters, 118 (1), pp. 012404, 2021.

    Links | BibTeX

    Wittrock, Steffen; Talatchian, Philippe; Romera, Miguel; Garcia, Mafalda Jotta; Cyrille, Marie-Claire; Ferreira, Ricardo; Lebrun, Romain; Bortolotti, Paolo; Ebels, Ursula; Grollier, Julie; others,

    Flicker and random telegraph noise between gyrotropic and dynamic C-state of a vortex based spin torque nano oscillator Journal Article

    AIP Advances, 11 (3), pp. 035042, 2021.

    Links | BibTeX

    Leroux, Nathan; Mizrahi, Alice; Markovic, Danijela; Sanz-Hernandez, Dedalo; Trastoy, Juan; Bortolotti, Paolo; Martins, Leandro; Jenkins, Alex; Ferreira, Ricardo; Grollier, Julie

    Hardware realization of the multiply and accumulate operation on radio-frequency signals with magnetic tunnel junctions Journal Article

    Neuromorphic Computing and Engineering, 2021.

    Abstract | Links | BibTeX

    Dionisio, Rogerio; Torres, Pedro; Ramalho, Armando; Ferreira, Ricardo

    Magnetoresistive Sensors and Piezoresistive Accelerometers for Vibration Measurements: A Comparative Study Journal Article

    Journal of Sensor and Actuator Networks, 10 (1), pp. 22, 2021.

    Links | BibTeX

    Jenkins, Alex S; Benetti, Luana ; Martins, Leandro ; Alvarez, Lara San Emeterio ; Ferreira, Ricardo

    Spintronic wireless sensor networkshttps Journal Article

    IEEE Transactions on Magnetics, pp. 1-1, 2021.

    Abstract | Links | BibTeX

  • 2020

    Tanwear, Asfand; Liang, Xiangpeng; Yuchi Liu, Aleksandra Vuckovic ; Ghannam, Rami; Böhnert, Tim; Paz, Elvira; Freitas, Paulo P; Ferreira, Ricardo; Heidari, Hadi

    Spintronic Sensors Based on Magnetic Tunnel Junctions for Wireless Eye Movement Gesture Control Journal Article

    IEEE Transactions on Biomedical Circuits and Systems, (14), pp. 1299 - 1310, 2020, ISBN: 1940-9990.

    Abstract | Links | BibTeX

    Danijela Markovic and Nathan Leroux and Alice Mizrahi and Juan Trastoy and Vincent Cros and Paolo Bortolotti and Leandro Martins and Alex Jenkins and Ricardo Ferreira and Julie Grollier

    Detection of the Microwave Emission from a Spin-Torque Oscillator by a Spin Diode Journal Article

    Phys. Rev. Applied, 13 , pp. 044050, 2020.

    Links | BibTeX

    Siming Zuo and Kianoush Nazarpour and Tim Böhnert and Ricardo Ferreira and Hadi Heidari

    Integrated Pico-Tesla Resolution Magnetoresistive Sensors for Miniaturised Magnetomyography Miscellaneous

    2020, (The work of KN is supported by grants EP/N023080/1 and EP/R004242/1 from
    EPSRC, UK.)
    .

    Abstract | Links | BibTeX

    Alex S Jenkins and Lara San Emeterio Alvarez and Roberta Dutra and Ruben L Sommer and Paulo P Freitas and Ricardo Ferreira

    Wideband High-Resolution Frequency-to-Resistance Converter Based on Nonhomogeneous Magnetic-State Transitions Journal Article

    Phys. Rev. Applied, 13 , pp. 014046, 2020.

    Links | BibTeX

    Tim Böhnert

    Magnetic Nano- and Microwires: Design, Synthesis, Properties and Applications (Woodhead Publishing Series in Electronic and Optical Materials) Book

    Woodhead Publishing, 2020, ISBN: 9780081028322.

    Links | BibTeX

  • 2019

    H Farkhani and T Bohnert and M Tarequzzaman and D Costa and A Jenkins and R Ferreira and F Moradi

    Spin-Torque-Nano-Oscillator based neuromorphic computing assisted by laser Inproceedings

    2019 14th International Conference on Design & Technology of Integrated Systems In Nanoscale Era (DTIS), IEEE, 2019.

    Links | BibTeX

    M Tarequzzaman and T Böhnert and M Decker and J D Costa and J Borme and B Lacoste and E Paz and A S Jenkins and S Serrano-Guisan and C H Back and R Ferreira and P P Freitas

    Spin torque nano-oscillator driven by combined spin injection from tunneling and spin Hall current Journal Article

    Communications Physics, 2 (1), pp. 20, 2019, ISSN: 2399-3650.

    Abstract | Links | BibTeX

    Marilia Barreiros dos Santos and Raquel B Queirós and Álvaro Geraldes and Carlos Marques and Vania Vilas-Boas and Lorena Dieguez and Elvira Paz and Ricardo Ferreira and Joao Morais and Vitor Vasconcelos and others

    Portable sensing system based on electrochemical impedance spectroscopy for the simultaneous quantification of free and total microcystin-LR in freshwaters Journal Article

    Biosensors and Bioelectronics, 142 , pp. 111550, 2019.

    Links | BibTeX

    Pedro Torres and Rogério Dionisio and Sérgio Malhao and Luis Neto and Ricardo Ferreira and Helena Gouveia and Hélder Castro

    Cyber-Physical Production Systems supported by Intelligent Devices (SmartBoxes) for Industrial Processes Digitalization Inproceedings

    2019 IEEE 5th International forum on Research and Technology for Society and Industry (RTSI), pp. 73–78, IEEE 2019.

    Links | BibTeX

    Hooman Farkhani and Tim Böhnert and Mohammad Tarequzzaman and José Diogo Costa and Alex Jenkins and Ricardo Ferreira and Jens Kargaard Madsen and Farshad Moradi

    LAO-NCS: Laser Assisted Spin Torque Nano Oscillator-Based Neuromorphic Computing System Journal Article

    Frontiers in Neuroscience, 13 , 2019.

    Links | BibTeX

    Sheng Jiang and Martina Ahlberg and Sunjae Chung and A Houshang and R Ferreira and PP Freitas and Johan Åkerman

    Magnetodynamics in orthogonal nanocontact spin-torque nano-oscillators based on magnetic tunnel junctions Journal Article

    Applied Physics Letters, 115 (15), pp. 152402, 2019.

    Links | BibTeX

    Alex S Jenkins and Lara San Emeterio Alvarez and Paulo P Freitas and Ricardo Ferreira

    Nanoscale true random bit generator based on magnetic state transitions in magnetic tunnel junctions Journal Article

    Scientific reports, 9 (1), pp. 1–6, 2019.

    Links | BibTeX

    Hooman Farkhani and Tim Böhnert and Mohammad Tarequzzaman and Diogo Costa and Alex Jenkins and Ricardo Ferreira and Farshad Moradi

    Spin-Torque-Nano-Oscillator based neuromorphic computing assisted by laser Inproceedings

    2019 14th International Conference on Design & Technology of Integrated Systems In Nanoscale Era (DTIS), pp. 1–5, IEEE 2019.

    Links | BibTeX

    Elvira Paz and Ricardo Ferreira and Paulo P Freitas

    Tuning the linear range of magnetic sensors based on MTJs (Conference Presentation) Inproceedings

    Spintronics XII, pp. 110903N, International Society for Optics and Photonics 2019.

    Links | BibTeX

  • 2018

    A Houshang and R Khymyn and H Fulara and A Gangwar and M Haidar and S R Etesami and R Ferreira and P P Freitas and M Dvornik and R K Dumas and J Åkerman

    Spin transfer torque driven higher-order propagating spin waves in nano-contact magnetic tunnel junctions Journal Article

    Nature Communications, 9 (1), 2018.

    Links | BibTeX

    H F Yang and F Garcia-Sanchez and X K Hu and S Sievers and T Böhnert and J D Costa and M Tarequzzaman and R Ferreira and M Bieler and H W Schumacher

    Excitation and coherent control of magnetization dynamics in magnetic tunnel junctions using acoustic pulses Journal Article

    Applied Physics Letters, 113 (7), pp. 072403, 2018.

    Links | BibTeX

    H F Yang and X K Hu and S Sievers and T Bohnert and J D Costa and M Tarequzzaman and R Ferreira and M Bieler and H W Schumacher

    Coherent Control of Acoustic-Wave-Induced Magnetization Dynamics in Magnetic Tunnel Junctions Inproceedings

    2018 Conference on Precision Electromagnetic Measurements, IEEE, 2018.

    Links | BibTeX

    M Tarequzzaman and A S Jenkins and T Böhnert and J Borme and L Martins and E Paz and R Ferreira and P P Freitas

    Broadband voltage rectifier induced by linear bias dependence in CoFeB/MgO magnetic tunnel junctions Journal Article

    Applied Physics Letters, 112 (25), pp. 252401, 2018, (arXiv: 1804.04104).

    Abstract | Links | BibTeX

    T Böhnert and E Paz and R Ferreira and P P Freitas

    Magnetic tunnel junction thermocouple for thermoelectric power harvesting Journal Article

    Physics Letters A, 2018, ISSN: 0375-9601.

    Links | BibTeX

    K J Merazzo and T Costa and F Franco and R Ferreira and M Zander and M Türr and T Becker and P P Freitas and S Cardoso

    Reading magnetic ink patterns with magnetoresistive sensors Journal Article

    AIP Advances, 8 (5), pp. 056633, 2018.

    Links | BibTeX

    M Tarequzzaman and T Bohnert and A S Jenkins and J Borme and E Paz and R Ferreira and P P Freitas

    Influence of MgO Tunnel Barrier Thickness on the Output Power of Three-Terminal Spin Hall Nano-Oscillators Journal Article

    IEEE Transactions on Magnetics, pp. 1–4, 2018.

    Links | BibTeX

    R Ferreira and E Paz

    Magnetoresistive sensor Patent

    US20180180686A1, 2018.

    Abstract | Links | BibTeX

  • 2017

    A V Silva and R Ferreira and E Paz and D C Leitao and T Devolder and S Cardoso and P P Freitas

    Thermal FMR Spectral Characterization of Very Low RA In-Plane MgO Magnetic Tunnel Junctions Journal Article

    IEEE Transactions on Magnetics, 53 (11), pp. 1–5, 2017.

    Links | BibTeX

    E G Vidal and D R Muñoz and S I R Arias and J S Moreno and S Cardoso and R Ferreira and P P Freitas

    Electronic Energy Meter Based on a Tunnel Magnetoresistive Effect (TMR) Current Sensor Journal Article

    Materials, 10 (10), pp. 1134, 2017.

    Links | BibTeX

    J D Costa and S Serrano-Guisan and B Lacoste and A S Jenkins and T Böhnert and M Tarequzzaman and J Borme and F L Deepak and E Paz and J Ventura and R Ferreira and P P Freitas

    High power and low critical current density spin transfer torque nano-oscillators using MgO barriers with intermediate thickness Journal Article

    Scientific Reports, 7 (1), 2017.

    Links | BibTeX

    T Böhnert and S Serrano-Guisan and E Paz and B Lacoste and R Ferreira and P P Freitas

    Magnetic tunnel junctions with integrated thermometers for magnetothermopower measurements Journal Article

    Journal of Physics: Condensed Matter, 29 (18), pp. 185303, 2017.

    Abstract | Links | BibTeX

    M Kuepferling and F Garcia-Sanchez and T Böhnert and R Ferreira and R Dutra and R L Sommer and M Pasquale

    Influence of thermal gradients on the vortex dynamics in CoFeB MTJs Inproceedings

    2017 IEEE International Magnetics Conference (INTERMAG), pp. 1-1, 2017.

    Abstract | Links | BibTeX

    T Böhnert and R Dutra and R L Sommer and E Paz and S Serrano-Guisan and R Ferreira and P P Freitas

    Influence of the thermal interface resistance on the thermovoltage of a magnetic tunnel junction Journal Article

    Physical Review B, 95 , pp. 104441, 2017.

    Links | BibTeX

    L Martins and J Ventura and R Ferreira and P P Freitas

    Optimization of the buffer surface of CoFeB/MgO/CoFeB-based magnetic tunnel junctions by ion beam milling Journal Article

    Applied Surface Science, 424 , pp. 58 - 62, 2017, ISSN: 0169-4332, (7th International Conference on Advanced Nanomaterials, 2nd International Conference on Graphene Technology, 1st International Conference on Spintronics Materials).

    Abstract | Links | BibTeX

    H F Yang and X K Hu and N Liebing and T Böhnert and J D Costa and M Tarequzzaman and R Ferreira and S Sievers and M Bieler and H W Schumacher

    Electrical measurement of absolute temperature and temperature transients in a buried nanostructure under ultrafast optical heating Journal Article

    Applied Physics Letters, 110 (23), pp. 232403, 2017.

    Links | BibTeX

  • 2016

    T J Huisman and R V Mikhaylovskiy and J D Costa and F Freimuth and E Paz and J Ventura and P P Freitas and S Blügel and Y Mokrousov and Th. Rasing and T Kimel

    Femtosecond control of electric currents in metallic ferromagnetic heterostructures Journal Article

    Nature Nanotechnology, 11 , pp. 455, 2016.

    Links | BibTeX

    S Knudde and G Farinha and D C Leitao and R Ferreira and S Cardoso and P P Freitas

    AlOx barrier growth in magnetic tunnel junctions for sensor applications Journal Article

    Journal of Magnetism and Magnetic Materials, 412 , pp. 181-184, 2016.

    Links | BibTeX

    M Romera and P Talatchian and R Lebrun and K J Merazzo and P Bortolotti and L Vila and J D Costa and R Ferreira and P P Freitas and M C Cyrille and U Ebels and V Cros and J Grollier

    Enhancing the injection locking range of spin torque oscillators through mutual coupling Journal Article

    Applied Physics Letters, 109 (25), 2016.

    Links | BibTeX

    E Paz and R Ferreira and P P Freitas

    Linearization of Magnetic Sensors With a Weakly Pinned Free-Layer MTJ Stack Using a Three-Step Annealing Process Journal Article

    IEEE Transactions on Magnetics, 52 (7), 2016.

    Links | BibTeX

    P P Freitas and R Ferreira and S Cardoso

    Spintronic Sensors Journal Article

    Proceedings of the IEEE, 104 (10), pp. 1894-1918, 2016.

    Links | BibTeX

  • 2015

    Ravelo S I Arias and Ramírez D Muñoz and S Cardoso and R Ferreira and P P Freitas

    Note: A non-invasive electronic measurement technique to measure the embedded four resistive elements in a Wheatstone bridge sensor Journal Article

    Review of Scientific Instruments, 86 (6), pp. 066109, 2015.

    Links | BibTeX

    A Ravelo and I Sergio and D Ramirez and S Cardoso and R Ferreira and P P Freitas

    Total ionizing dose (TID) evaluation of magnetic tunnel junction (MTJ) current sensors Journal Article

    Sensors and Actuators a-Physical, 225 (119-127), 2015.

    BibTeX

    J Valadeiro and J Amaral and D C Leitao and R Ferreira and S Cardoso and P P Freitas

    Strategies for pTesla Field Detection Using Magnetoresistive Sensors With a Soft Pinned Sensing Layer Journal Article

    IEEE Trans. Magn, 51 (1), pp. 4400204, 2015.

    BibTeX

    S Sievers and N Liebing and S Serrano-Guisan and R Ferreira and E Paz and A Caprile and A Manzin and M Pasquale and W Skowronski and T Stobiecki and K Rott and G Reiss and J Langer and B Ocker and H W Schumacher

    Toward Wafer Scale Inductive Characterization of Spin-Transfer Torque Critical Current Density of Magnetic Tunnel Junction Stacks Journal Article

    IEEE Trans. Magn, 51 (1), pp. 1400804, 2015.

    Links | BibTeX

    A Caprile and A Manzin and M Coisson and M Pasquale and H W Schumacher and N Liebing and S Sievers and R Ferreira and S Serrano-Guisan and E Paz

    Static and Dynamic Analysis of Magnetic Tunnel Junctions With Wedged MgO Barrier Journal Article

    IEEE Trans. Magn, 51 (1), pp. 4400304, 2015.

    Links | BibTeX

    J D Costa and S Serrano-Guisan and J Borme and F L Deepak and M Tarequzzaman and E Paz and J Ventura and R Ferreira and P P Freitas

    Impact of MgO Thickness on the Performance of Spin-Transfer Torque Nano-Oscillators Journal Article

    IEEE Transactions on Magnetics , 51 (11), 2015.

    Links | BibTeX

    M Costa and J Gaspar and R Ferreira and E Paz and H Fonseca and M Martins and S Cardoso and P P Freitas

    Integration of magnetoresistive sensors with atomic force microscopy cantilevers for scanning magnetoresistance microscopy applications Journal Article

    IEEE Transactions on Magnetics, 51 , 2015.

    BibTeX

    D C Leitao and A V Silva and E Paz and R Ferreira and S Cardoso and P P Freitas

    Magnetoresistive nanosensors: controlling magnetism at the nanoscale Journal Article

    Nanotechnology, 27 (4), 2015.

    BibTeX

  • 2014

    D C Leitao and E Paz and A Silva and A Moskaltsova and S Knudde and F L Deepak and R Ferreira and S Cardoso and P P Freitas

    Nanoscale Magnetic Tunnel Junction Sensing Devices With Soft Pinned Sensing Layer and Low Aspect Ratio Journal Article

    IEEE Trans. Magn, 50 (11), pp. 4410508, 2014.

    Links | BibTeX

    F A Cardoso and L S Rosado and F Franco and R Ferreira and E Paz and S Cardoso and P M Ramos and M Piedade and P P Freitas

    Improved Magnetic Tunnel Junctions Design for the Detection of Superficial Defects by Eddy Currents Testing Journal Article

    IEEE Trans. Magn, 50 (11), pp. 6201304, 2014.

    Links | BibTeX

    X Q Bao and R Ferreira and E Paz and D Leitao and A Silva and S Cardoso and P P Freitas and L F.Liu

    Ordered arrays of tilted silicon nanobelts with enhanced solar hydrogen evolution performance Journal Article

    Nanoscale, 6 , pp. 2097-2101, 2014.

    BibTeX

    A Roldán and J B Roldán and C Reig and S Cardoso and F Cardoso and R Ferreira and P P Freitas

    An in-depth noise model for giant magnetoresistance current sensors for circuit design and complementary metal–oxide–semiconductor integration Journal Article

    Journal of Applied Physics, 115 (17), pp. 17E514, 2014.

    Links | BibTeX

    S Cardoso and D C Leitao and L Gameiro and F Cardoso and R Ferreira and E Paz and P P Freitas

    Magnetic tunnel junction sensors with pTesla sensitivity Journal Article

    Microsyst. Technol., 20 , pp. 793-802, 2014.

    BibTeX

    Z Hou and A Silva and D C Leitao and R Ferreira and S Cardoso and P P Freitas

    Micromagnetic and magneto-transport simulations of nanodevices based on MgO tunnel junctions for memory and sensing applications Journal Article

    Physica B: Condensed Matter, 435 , pp. 163-167, 2014.

    Links | BibTeX

    D W Guo and F A Cardoso and R Ferreira and E Paz and S Cardoso and P P Freitas

    MgO-based magnetic tunnel junction sensors array for non-destructive testing applications Journal Article

    J. Appl. Phys., 115 , pp. 17E513, 2014.

    Links | BibTeX

    F A Cardoso and L Rosado and R Ferreira and E Paz and S Cardoso and P M Ramos and M Piedade and P P Freitas

    Magnetic tunnel junction based eddy current testing probe for detection of surface defects Journal Article

    J. Appl. Phys., 115 (17), pp. 15E16, 2014.

    Links | BibTeX

    D C Leitao and A Silva and R Ferreira and E Paz and F L Deepack and S Cardoso and P P Freitas

    Linear nanometric tunnel junction sensors with exchange pinned sensing layer Journal Article

    J. App. Phys., 115 (17), pp. 17E526, 2014.

    Links | BibTeX

  • 2013

    E Paz and S Serrano-Guisan and R Ferreira and P P Freitas

    Room temperature direct detection of low frequency magnetic fields in the 100 pT/Hz(0.5) range using large arrays of magnetic tunnel junctions Journal Article

    J. App. Phys., 115 (17), pp. 17E501, 2013.

    Links | BibTeX

    A Silva and D Leitao and Z Huo and R Macedo and R Ferreira and E Paz and F L Deepak and S Cardoso and P P Freitas

    Switching Field Variation in MgO Magnetic Tunnel Junction Nanopillars: Experimental Results and Micromagnetic Simulations Journal Article

    IEEE Trans. Magn, 49 (7), pp. 4405-4408, 2013.

    BibTeX

    A Lopes and S Cardoso and R Ferreira and E Paz and F L Deepak and J Sanchez and D Ramirez and S Ravelo and P P Freitas

    MgO Magnetic Tunnel Junction Electrical Current Sensor With Integrated Ru Thermal Sensor Journal Article

    IEEE Trans. Magn, 49 (7), pp. 3866-3869, 2013.

    Links | BibTeX

    J Amaral and V Pinto and T Costa and J Gaspar and R Ferreira and E Paz and S Cardoso and P P Freitas

    Integration of TMR Sensors in Silicon Microneedles for Magnetic Measurements of Neurons Journal Article

    IEEE Trans. Magn, 49 (7), pp. 3515-3515, 2013.

    Links | BibTeX

    S Cardoso and L Gameiro and D C Leitao and F Cardoso and R Ferreira and E Paz and P P Freitas and U Schmid and J Aldavero and M LeesterSchaede

    Magnetic tunnel junction sensors with pTesla sensitivity for biomedical imaging Journal Article

    Smart Sensors, Actuators, and Mems, pp. 8763, 2013.

    Links | BibTeX

    F Delgado and K Lopez and R Ferreira and J Fernández-Rossier

    Intrinsic Spin Noise in MgO Magnetic Tunnel Junctions Journal Article

    Appl. Phys. Lett., 102 (63102), 2013.

    Links | BibTeX

    N Liebing and S Serrano-Guisan and P Krzysteczko and K Rott and G Reiss and J Langer and B Ocker and H W Schumacher

    Tunneling magneto thermocurrent in CoFeB/MgO/CoFeB based magnetic tunnel junctions Journal Article

    Applied Physics Letters, 102 (24), pp. 242413, 2013.

    Links | BibTeX

  • 2012

    S Arias and D Munoz and J Moreno and S Cardoso and R Ferreira and P P Freitas

    Fractional Modeling of the AC Large-Signal Frequency Response in Magnetoresistive Current Sensors Journal Article

    Sensors, 13 (12), pp. 17516-17533, 2012.

    Links | BibTeX

    J Ventura and J M Teixeira and E Paz and J S Amaral and J D Costa and J P Araujo and S Cardoso and R Ferreira and P P Freitas

    The influence of annealing on the bimodal distribution of blocking temperatures of exchange biased bilayers Journal Article

    Phys. Status Solidi RRL, 7 (9), pp. 676-680, 2012.

    BibTeX

    R Ferreira and E Paz and P P Freitas and J Wang and S Xue

    Large Area and Low Aspect Ratio Linear Magnetic Tunnel Junctions with a Soft-Pinned Sensing Layer Journal Article

    IEEE Trans. Magn, 48 (11), pp. 3719, 2012.

    Links | BibTeX

    R Ferreira and E Paz and P P Freitas and J Ribeiro and J Germano and L Sousa

    2-axis Magnetometers Based on Full Wheatstone Bridges Incorporating Magnetic Tunnel Junctions Connected in Series Journal Article

    IEEE Trans. Magn, 48 (11), pp. 4107, 2012.

    Links | BibTeX

    J Sanchez and D Ramirez and S Ravelo and A Lopes and S Cardoso and R Ferreira and P P Freitas

    Electrical Characterization of a Magnetic Tunnel Junction Current Sensor for Industrial Applications Journal Article

    IEEE Trans. Magn, 48 (11), pp. 2823, 2012.

    Links | BibTeX

    R J Janeiro and L Gameiro and A Lopes and S Cardoso and R Ferreira and E Paz and P P Freitas

    Linearization and Field Detectivity in Magnetic Tunnel Junction Sensors Connected in Series Incorporating 16nm-thick NiFe Free Layers Journal Article

    IEEE Trans. Magn, 48 (11), pp. 4111, 2012.

    Links | BibTeX

GROUP LEADER

ricardo_ferreira_web

THE TEAM

Alex Jenkins
Staff Researcher

Elvira Paz
Staff Researcher

Tim Böhnert
Staff Researcher

Luana Benetti
Research Fellow

Marcel Claro
Research Fellow

also on the picture

Cosimo Spagnolo and Mohamed Belmoubarik
Research Engineers from Nanodevices

Oscar Ojeda Toro
Visitor from Universidade Federal de Santa Maria and Universidade Federal de Viçosa

Arthur de Sousa Lopes Moreira and Marion Vieira
Master students from Université Clermont Auvergne (UCA)

Lianwei Wang, En Ping Tu and Hefu Han
from LerTech Co.,Ltd

Previous Members

Lara San-Emeterio

Diogo Costa
Moved to IMEC after working at INL during 2013-2017

Bertrand Lacoste
Moved to Champalimaud after working at INL during 2013-2015

Mohammad Tarequzzaman
Moved to Analog Devices after working at INL during 2013-2018

Santiago Serrano-Guisan
Moved to Headway after working at INL during 2013-2015

Spintronics Research Group

Spintronics is a research area trying to take profit from the spin of the electrons as a mean to obtain, transmit and process information. The spin of the electrons is a degree of freedom that is not explored by conventional electronics rely only on the electrical charge to drive electronic circuits. Spintronics use magnetic materials patterned at the nano-scale to produce spin polatized currents which drive a new class of beyond CMOS components which include magnetic field sensors, non-volatile memories and RF devices.

group-picture-052018_smaller

Spintronics research team (picture from April 2018)

RESEARCH LINES

TT00000414_20170321_112923MAGNETIC ANNEALING SYSTEM (MATr 2000)

The MATR is a system used for annealing at elevated temperatures (up to 400 °C) in the presence of intense magnetic fields (up to 2 Tesla).  Such magnetic fields are generated by a superconducting magnet module created by running current through windings of this material.  The system can handle multiple wafers of 200mm and 150mm in diameter, in parallel or perpendicular position with respect to the magnetic field. There is also a 1×1 inch sample holder available.

TT00000886_20151126_125506UHV multitarget confocal sputtering tool (Kenosistec)

A multi-target UHV sputtering system consisting of a deposition chamber with 11 2” diameter magnetrons in confocal geometry for the co-deposition of materials, optimized wafers of up to 200m in diameter.

TT00000889_20151126_125735TiW, AlSiCu and Al2O3 sputtering (Timaris FTM)

The Four-Target-Module (FTM) physical vapor deposition cluster tool is especially designed for deposition of high–quality metallic, conductive and insulating films. The system is a UHV single wafer cluster tool and consists of one transport module, one multi-target PVD module with up to four DC/RF cathodes (three targets are install in this machine AlSiCu, TiW and Al2O3) and one soft etch/oxidation module. It is capable of depositing different magnetic and non–magnetic layers on wafers with diameters up to 200mm by DC/RF Magnetron Sputtering, with good uniformity for the deposited films. The FTM incorporates Linear Dynamic Deposition (LDD) technology in combination with up to four sputter targets in one vacuum chamber. The LDD technology enables the capability to deposit wedge films with a different film thickness across the wafer and to deposit alloy films with adjustable concentration gradients across one wafer.

TT00000884_20151126_125713Mutitarget sputtering tool (Timaris MTM)

The Multi-Target Module (MTM) physical vapor deposition cluster tool is especially designed for deposition of ultra–thin films, magnetic films, high–quality metallic, conductive and insulating films and multiple film stack deposition comprising these materials without the need to break ultra-high vacuum. The system is a UHV single wafer cluster tool and consists of one transport module, one multi-target PVD module with 10 DC/RF cathodes and one soft etch/oxidation module. It is capable of depositing different magnetic and non–magnetic layers on wafers with diameters up to 200mm by DC/RF Magnetron Sputtering (or Ion Beam Sputtering), with good uniformity for the deposited stacks.
Additional features such as wafer heating for hot substrate deposition or a collinear Aligning Magnetic Field (AMF) are available. The AMF can be activated to align the magnetic easy axis during deposition of ferromagnetic films.
The Linear Dynamic Deposition (LDD) technology enables the capability to deposit wedge films with a different film thickness across the wafer and to deposit alloy films with adjustable concentration gradients across one wafer. Both features allow a very cost effective development of film stacks and accelerate the devices development.

CIPTCurrent in-plane tester (CIPT)
To verify the transport properties of MTJs before nanofabrication a  CIPT is used to perform TMR and RA measurements of bulk MTJ stacks. This is a very useful tool since it allows us to retrieve fundamental information of the MTJ stack prior to fabrication. To perform these measurements, the system contacts 12 cantilever electrodes with a variable spacing, down to 750 nm. It performs electrical measurements (current and voltage) through the different cantilevers with different spacing between them. This allows to determine the RA and TMR. The CIPT can determine RA values down to 0.1 Wμm² and measure the TMR with both in-plane and perpendicular anisotropy with in-plane fields up to 2500 Oe and perpendicular fields up to 1400 Oe.

VSMVibrating Sample Magnetometer (VSM)
The VSM allows the measurement of the magnetic moment as a function of the applied magnetic field of unpatterned samples. Thus, it allowed us to measure and optimize the magnetic stacks and annealings used during this project. The used VSM system can measure magnetic signals down to 5⋅10^-7 emu and very low coercivities (10 mOe; field resolution) and can apply fields up to 2 T. It allows the fast and accurate measurement of the magnetic moment, not only as a function of the applied magnetic field, but also with temperature (which can be swept from 83 to 570 K). Angular and time dependences of the magnetization can be measured as well.

automated_proberAutomatic Transport Measurement Setup
Once the MTJ fabrication process is complete, this setup does a full characterization of thousands of MTJ devices on the full wafer. A system with 40 tips is used to characterized 10 MTJs in a 4-contact scheme per landing site. Statistically meaningful data regarding the device TMR, RA, shape of the transfer curves, and corresponding deviations arising from the nanofabrication process are obtained. Furthermore, a software allows a collecting different figures of merit (TMR, RA, coercive field, linear range of the curve, etc) and organize them for different parameters (die number, pillar sizes, TMR and RA range, etc).

IP_proberRF prober for in-plane magnetic fields
Electrical contact to characterize RF devices was performed using special Cascade Microtech’s probes. These probes allow high accuracy RF measurements with low contact resistance. An optical microscope in conjugation with holders that allow high accuracy movements (both for the sample and the tips) are used to connect the contacts to the device. The RF measurements can be performed while injecting a DC current in the MTJ. Moreover, synchronization and spin diode torque studies can also be performed since an RF signal can be provided to the MTJ and the generated DC voltage measured. The signal is then transported through coaxial cables to a 3 Hz – 44 GHz spectrum analyzer where the emission spectrum can be acquired. Power suppliers are used to provide current both to the MTJ and the magnet. Automated control of the complete system can be performed to make sequences with different values of current and magnetic field. An amplifier is usually used to increase the measured signal, although its use was not necessary in the cases of MTJs with high output power. A bias tee is used to separate the DC and RF electrical components (being the last one sent to the spectrum analyzer). The magnetic field was applied using a small magnet. The orientation of the magnet could be manually changed but it was limited to relatively small magnetic fields (up to 200 Oe) in the in-plane direction.

OOP_proberRF prober for out-of-plane magnetic fields
A similar to the IP measurement setup this is an RF measurement setup with power supplies and spectrum analyzer, but for out-of-plane magnetic fields. Magnetic fields up to 1.6 T can be applied. The magnetic can be rotated between in-plane and out-of-plane direction with a highly precise stepper motor. The applied magnetic field value can be measured directly using a gaussmeter. The setup requires the positioning of the tips with the aid of an optical microscope. After the tips are properly connected to the contacts the microscope is easily displaced and the magnet positioned in the sample position.

p2020MAGLINE
Project Time Frame: Apr 2017 to Jan 2020
MAGLINE: Desenvolvimento e Validação Industrial do Processo de Fabricação de Sensores TMR
The latest generation of sensors (TMR) has major advantages over previous (Hall and GMR), and there is a market with sustained growth for application of these sensors. However the lack of industrial production capacity prevents its adoption in large scale commercial applications, although it is possible to acquire them commercially those marketed generic sensors are not optimized for any particular application. There is a clear opportunity to capture this market, and provide the market a large-scale production solution TMR sensors optimized and custom-made for different applications.

PRODUTECH-SIF
Project Time Frame: Nov 2017 to Sep 2020
The project embodies a comprehensive response towards the development and implementation of new production systems, embedding advanced production technologies that will equip the manufacturing industry to meet the challenges and opportunities of the 4th industrial revolution.

INFANTE
Project Time Frame: Nov 2017 to Sep 2020
INFANTE is a development and demonstration project for an in-orbit microsatellite, to be launched in 2020. This is the precursor of a constellation for Earth observation and communication with the focus on maritime applications.
INFANTE will be the first satellite developed by the Portuguese Industry, articulated in a national consortium led by TEKEVER group, that includes 9 companies with references in the space sector, as Active Space Technologies, Omnidea, Active Aerogels, GMV, HPS and Spinworks; and 10 internationally recognized R&D Centers in their areas of competence, such as CEIIA; FEUP, ISQ, FCT-UNL, INL, IPN, IPTomar, ISR Lisbon, IT Aveiro, and UBI.

MOSAIC
Project Time Frame: Jan 2013 to Sep 2016
The broader objective is to bring the device level knowledge acquired in the past years by the partners towards systems as a first crucial step towards industrialization, warranting the leading position not only of European research but also of European industry in microwave spintronics.

SPINICUR webpage
Project Time Frame: Oct. 2012- Mar. 2016
SPINICUR (from spin currents) is a training network of European experts dedicated to providing state-of-the-art education and training for early stage and experienced researchers. We have concentrated on an aspect of spintronics – pure spin currents – and specific technical goals in order to secure a very high level of industrial involvement and strong network connectivity through a sharp focus.

SpinCal webpage
Project Time Frame: Jul. 2013 – Jun. 2016
SpinCal stands for Spintronics and spin-caloritronics in magnetic nanosystems, a joint research project (JRP) funded by the European Metrology Research Programme (EMRP). The aim of the project is to enable fundamental understanding of new effects emerging in the field of spintronics and spin-caloritronics in magnetic nanosystems. This goal was achieved by developing a new measurement infrastructure and a best practice guide for spin-caloritronic material measurements, providing a road map towards future standardisation of spintronic and spin-caloritronic measurements, materials and devices.

INTEGRATION
Project Time Frame: 2012-2015
Towards hybrid integrated heterogeneous technology devices.

PERPENDICULAR (PTDC-CTM-MET-118236-2010) webpage
Project Time Frame: Jul. 2012- Jun. 2014
Advanced MRAM Structures using Perpendicular Magnetization Materials for Spin Transfer Writing.

PUBLICATIONS

  • 2020

    Tanwear, Asfand; Liang, Xiangpeng; Yuchi Liu, Aleksandra Vuckovic ; Ghannam, Rami; Böhnert, Tim; Paz, Elvira; Freitas, Paulo P; Ferreira, Ricardo; Heidari, Hadi

    Spintronic Sensors Based on Magnetic Tunnel Junctions for Wireless Eye Movement Gesture Control Journal Article

    IEEE Transactions on Biomedical Circuits and Systems, (14), pp. 1299 - 1310, 2020, ISBN: 1940-9990.

    Abstract | Links | BibTeX

    Danijela Markovic and Nathan Leroux and Alice Mizrahi and Juan Trastoy and Vincent Cros and Paolo Bortolotti and Leandro Martins and Alex Jenkins and Ricardo Ferreira and Julie Grollier

    Detection of the Microwave Emission from a Spin-Torque Oscillator by a Spin Diode Journal Article

    Phys. Rev. Applied, 13 , pp. 044050, 2020.

    Links | BibTeX

    Siming Zuo and Kianoush Nazarpour and Tim Böhnert and Ricardo Ferreira and Hadi Heidari

    Integrated Pico-Tesla Resolution Magnetoresistive Sensors for Miniaturised Magnetomyography Miscellaneous

    2020, (The work of KN is supported by grants EP/N023080/1 and EP/R004242/1 from
    EPSRC, UK.)
    .

    Abstract | Links | BibTeX

    Alex S Jenkins and Lara San Emeterio Alvarez and Roberta Dutra and Ruben L Sommer and Paulo P Freitas and Ricardo Ferreira

    Wideband High-Resolution Frequency-to-Resistance Converter Based on Nonhomogeneous Magnetic-State Transitions Journal Article

    Phys. Rev. Applied, 13 , pp. 014046, 2020.

    Links | BibTeX

    Tim Böhnert

    Magnetic Nano- and Microwires: Design, Synthesis, Properties and Applications (Woodhead Publishing Series in Electronic and Optical Materials) Book

    Woodhead Publishing, 2020, ISBN: 9780081028322.

    Links | BibTeX

  • 2019

    H Farkhani and T Bohnert and M Tarequzzaman and D Costa and A Jenkins and R Ferreira and F Moradi

    Spin-Torque-Nano-Oscillator based neuromorphic computing assisted by laser Inproceedings

    2019 14th International Conference on Design & Technology of Integrated Systems In Nanoscale Era (DTIS), IEEE, 2019.

    Links | BibTeX

    M Tarequzzaman and T Böhnert and M Decker and J D Costa and J Borme and B Lacoste and E Paz and A S Jenkins and S Serrano-Guisan and C H Back and R Ferreira and P P Freitas

    Spin torque nano-oscillator driven by combined spin injection from tunneling and spin Hall current Journal Article

    Communications Physics, 2 (1), pp. 20, 2019, ISSN: 2399-3650.

    Abstract | Links | BibTeX

    Marilia Barreiros dos Santos and Raquel B Queirós and Álvaro Geraldes and Carlos Marques and Vania Vilas-Boas and Lorena Dieguez and Elvira Paz and Ricardo Ferreira and Joao Morais and Vitor Vasconcelos and others

    Portable sensing system based on electrochemical impedance spectroscopy for the simultaneous quantification of free and total microcystin-LR in freshwaters Journal Article

    Biosensors and Bioelectronics, 142 , pp. 111550, 2019.

    Links | BibTeX

    Pedro Torres and Rogério Dionisio and Sérgio Malhao and Luis Neto and Ricardo Ferreira and Helena Gouveia and Hélder Castro

    Cyber-Physical Production Systems supported by Intelligent Devices (SmartBoxes) for Industrial Processes Digitalization Inproceedings

    2019 IEEE 5th International forum on Research and Technology for Society and Industry (RTSI), pp. 73–78, IEEE 2019.

    Links | BibTeX

    Hooman Farkhani and Tim Böhnert and Mohammad Tarequzzaman and José Diogo Costa and Alex Jenkins and Ricardo Ferreira and Jens Kargaard Madsen and Farshad Moradi

    LAO-NCS: Laser Assisted Spin Torque Nano Oscillator-Based Neuromorphic Computing System Journal Article

    Frontiers in Neuroscience, 13 , 2019.

    Links | BibTeX

    Sheng Jiang and Martina Ahlberg and Sunjae Chung and A Houshang and R Ferreira and PP Freitas and Johan Åkerman

    Magnetodynamics in orthogonal nanocontact spin-torque nano-oscillators based on magnetic tunnel junctions Journal Article

    Applied Physics Letters, 115 (15), pp. 152402, 2019.

    Links | BibTeX

    Alex S Jenkins and Lara San Emeterio Alvarez and Paulo P Freitas and Ricardo Ferreira

    Nanoscale true random bit generator based on magnetic state transitions in magnetic tunnel junctions Journal Article

    Scientific reports, 9 (1), pp. 1–6, 2019.

    Links | BibTeX

    Hooman Farkhani and Tim Böhnert and Mohammad Tarequzzaman and Diogo Costa and Alex Jenkins and Ricardo Ferreira and Farshad Moradi

    Spin-Torque-Nano-Oscillator based neuromorphic computing assisted by laser Inproceedings

    2019 14th International Conference on Design & Technology of Integrated Systems In Nanoscale Era (DTIS), pp. 1–5, IEEE 2019.

    Links | BibTeX

    Elvira Paz and Ricardo Ferreira and Paulo P Freitas

    Tuning the linear range of magnetic sensors based on MTJs (Conference Presentation) Inproceedings

    Spintronics XII, pp. 110903N, International Society for Optics and Photonics 2019.

    Links | BibTeX

  • 2018

    A Houshang and R Khymyn and H Fulara and A Gangwar and M Haidar and S R Etesami and R Ferreira and P P Freitas and M Dvornik and R K Dumas and J Åkerman

    Spin transfer torque driven higher-order propagating spin waves in nano-contact magnetic tunnel junctions Journal Article

    Nature Communications, 9 (1), 2018.

    Links | BibTeX

    H F Yang and F Garcia-Sanchez and X K Hu and S Sievers and T Böhnert and J D Costa and M Tarequzzaman and R Ferreira and M Bieler and H W Schumacher

    Excitation and coherent control of magnetization dynamics in magnetic tunnel junctions using acoustic pulses Journal Article

    Applied Physics Letters, 113 (7), pp. 072403, 2018.

    Links | BibTeX

    H F Yang and X K Hu and S Sievers and T Bohnert and J D Costa and M Tarequzzaman and R Ferreira and M Bieler and H W Schumacher

    Coherent Control of Acoustic-Wave-Induced Magnetization Dynamics in Magnetic Tunnel Junctions Inproceedings

    2018 Conference on Precision Electromagnetic Measurements, IEEE, 2018.

    Links | BibTeX

    M Tarequzzaman and A S Jenkins and T Böhnert and J Borme and L Martins and E Paz and R Ferreira and P P Freitas

    Broadband voltage rectifier induced by linear bias dependence in CoFeB/MgO magnetic tunnel junctions Journal Article

    Applied Physics Letters, 112 (25), pp. 252401, 2018, (arXiv: 1804.04104).

    Abstract | Links | BibTeX

    T Böhnert and E Paz and R Ferreira and P P Freitas

    Magnetic tunnel junction thermocouple for thermoelectric power harvesting Journal Article

    Physics Letters A, 2018, ISSN: 0375-9601.

    Links | BibTeX

    K J Merazzo and T Costa and F Franco and R Ferreira and M Zander and M Türr and T Becker and P P Freitas and S Cardoso

    Reading magnetic ink patterns with magnetoresistive sensors Journal Article

    AIP Advances, 8 (5), pp. 056633, 2018.

    Links | BibTeX

    M Tarequzzaman and T Bohnert and A S Jenkins and J Borme and E Paz and R Ferreira and P P Freitas

    Influence of MgO Tunnel Barrier Thickness on the Output Power of Three-Terminal Spin Hall Nano-Oscillators Journal Article

    IEEE Transactions on Magnetics, pp. 1–4, 2018.

    Links | BibTeX

    R Ferreira and E Paz

    Magnetoresistive sensor Patent

    US20180180686A1, 2018.

    Abstract | Links | BibTeX

  • 2017

    A V Silva and R Ferreira and E Paz and D C Leitao and T Devolder and S Cardoso and P P Freitas

    Thermal FMR Spectral Characterization of Very Low RA In-Plane MgO Magnetic Tunnel Junctions Journal Article

    IEEE Transactions on Magnetics, 53 (11), pp. 1–5, 2017.

    Links | BibTeX

    E G Vidal and D R Muñoz and S I R Arias and J S Moreno and S Cardoso and R Ferreira and P P Freitas

    Electronic Energy Meter Based on a Tunnel Magnetoresistive Effect (TMR) Current Sensor Journal Article

    Materials, 10 (10), pp. 1134, 2017.

    Links | BibTeX

    J D Costa and S Serrano-Guisan and B Lacoste and A S Jenkins and T Böhnert and M Tarequzzaman and J Borme and F L Deepak and E Paz and J Ventura and R Ferreira and P P Freitas

    High power and low critical current density spin transfer torque nano-oscillators using MgO barriers with intermediate thickness Journal Article

    Scientific Reports, 7 (1), 2017.

    Links | BibTeX

    T Böhnert and S Serrano-Guisan and E Paz and B Lacoste and R Ferreira and P P Freitas

    Magnetic tunnel junctions with integrated thermometers for magnetothermopower measurements Journal Article

    Journal of Physics: Condensed Matter, 29 (18), pp. 185303, 2017.

    Abstract | Links | BibTeX

    M Kuepferling and F Garcia-Sanchez and T Böhnert and R Ferreira and R Dutra and R L Sommer and M Pasquale

    Influence of thermal gradients on the vortex dynamics in CoFeB MTJs Inproceedings

    2017 IEEE International Magnetics Conference (INTERMAG), pp. 1-1, 2017.

    Abstract | Links | BibTeX

    T Böhnert and R Dutra and R L Sommer and E Paz and S Serrano-Guisan and R Ferreira and P P Freitas

    Influence of the thermal interface resistance on the thermovoltage of a magnetic tunnel junction Journal Article

    Physical Review B, 95 , pp. 104441, 2017.

    Links | BibTeX

    L Martins and J Ventura and R Ferreira and P P Freitas

    Optimization of the buffer surface of CoFeB/MgO/CoFeB-based magnetic tunnel junctions by ion beam milling Journal Article

    Applied Surface Science, 424 , pp. 58 - 62, 2017, ISSN: 0169-4332, (7th International Conference on Advanced Nanomaterials, 2nd International Conference on Graphene Technology, 1st International Conference on Spintronics Materials).

    Abstract | Links | BibTeX

    H F Yang and X K Hu and N Liebing and T Böhnert and J D Costa and M Tarequzzaman and R Ferreira and S Sievers and M Bieler and H W Schumacher

    Electrical measurement of absolute temperature and temperature transients in a buried nanostructure under ultrafast optical heating Journal Article

    Applied Physics Letters, 110 (23), pp. 232403, 2017.

    Links | BibTeX

  • 2016

    T J Huisman and R V Mikhaylovskiy and J D Costa and F Freimuth and E Paz and J Ventura and P P Freitas and S Blügel and Y Mokrousov and Th. Rasing and T Kimel

    Femtosecond control of electric currents in metallic ferromagnetic heterostructures Journal Article

    Nature Nanotechnology, 11 , pp. 455, 2016.

    Links | BibTeX

    S Knudde and G Farinha and D C Leitao and R Ferreira and S Cardoso and P P Freitas

    AlOx barrier growth in magnetic tunnel junctions for sensor applications Journal Article

    Journal of Magnetism and Magnetic Materials, 412 , pp. 181-184, 2016.

    Links | BibTeX

    M Romera and P Talatchian and R Lebrun and K J Merazzo and P Bortolotti and L Vila and J D Costa and R Ferreira and P P Freitas and M C Cyrille and U Ebels and V Cros and J Grollier

    Enhancing the injection locking range of spin torque oscillators through mutual coupling Journal Article

    Applied Physics Letters, 109 (25), 2016.

    Links | BibTeX

    E Paz and R Ferreira and P P Freitas

    Linearization of Magnetic Sensors With a Weakly Pinned Free-Layer MTJ Stack Using a Three-Step Annealing Process Journal Article

    IEEE Transactions on Magnetics, 52 (7), 2016.

    Links | BibTeX

    P P Freitas and R Ferreira and S Cardoso

    Spintronic Sensors Journal Article

    Proceedings of the IEEE, 104 (10), pp. 1894-1918, 2016.

    Links | BibTeX

  • 2015

    Ravelo S I Arias and Ramírez D Muñoz and S Cardoso and R Ferreira and P P Freitas

    Note: A non-invasive electronic measurement technique to measure the embedded four resistive elements in a Wheatstone bridge sensor Journal Article

    Review of Scientific Instruments, 86 (6), pp. 066109, 2015.

    Links | BibTeX

    A Ravelo and I Sergio and D Ramirez and S Cardoso and R Ferreira and P P Freitas

    Total ionizing dose (TID) evaluation of magnetic tunnel junction (MTJ) current sensors Journal Article

    Sensors and Actuators a-Physical, 225 (119-127), 2015.

    BibTeX

    J Valadeiro and J Amaral and D C Leitao and R Ferreira and S Cardoso and P P Freitas

    Strategies for pTesla Field Detection Using Magnetoresistive Sensors With a Soft Pinned Sensing Layer Journal Article

    IEEE Trans. Magn, 51 (1), pp. 4400204, 2015.

    BibTeX

    S Sievers and N Liebing and S Serrano-Guisan and R Ferreira and E Paz and A Caprile and A Manzin and M Pasquale and W Skowronski and T Stobiecki and K Rott and G Reiss and J Langer and B Ocker and H W Schumacher

    Toward Wafer Scale Inductive Characterization of Spin-Transfer Torque Critical Current Density of Magnetic Tunnel Junction Stacks Journal Article

    IEEE Trans. Magn, 51 (1), pp. 1400804, 2015.

    Links | BibTeX

    A Caprile and A Manzin and M Coisson and M Pasquale and H W Schumacher and N Liebing and S Sievers and R Ferreira and S Serrano-Guisan and E Paz

    Static and Dynamic Analysis of Magnetic Tunnel Junctions With Wedged MgO Barrier Journal Article

    IEEE Trans. Magn, 51 (1), pp. 4400304, 2015.

    Links | BibTeX

    J D Costa and S Serrano-Guisan and J Borme and F L Deepak and M Tarequzzaman and E Paz and J Ventura and R Ferreira and P P Freitas

    Impact of MgO Thickness on the Performance of Spin-Transfer Torque Nano-Oscillators Journal Article

    IEEE Transactions on Magnetics , 51 (11), 2015.

    Links | BibTeX

    M Costa and J Gaspar and R Ferreira and E Paz and H Fonseca and M Martins and S Cardoso and P P Freitas

    Integration of magnetoresistive sensors with atomic force microscopy cantilevers for scanning magnetoresistance microscopy applications Journal Article

    IEEE Transactions on Magnetics, 51 , 2015.

    BibTeX

    D C Leitao and A V Silva and E Paz and R Ferreira and S Cardoso and P P Freitas

    Magnetoresistive nanosensors: controlling magnetism at the nanoscale Journal Article

    Nanotechnology, 27 (4), 2015.

    BibTeX

  • 2014

    D C Leitao and E Paz and A Silva and A Moskaltsova and S Knudde and F L Deepak and R Ferreira and S Cardoso and P P Freitas

    Nanoscale Magnetic Tunnel Junction Sensing Devices With Soft Pinned Sensing Layer and Low Aspect Ratio Journal Article

    IEEE Trans. Magn, 50 (11), pp. 4410508, 2014.

    Links | BibTeX

    F A Cardoso and L S Rosado and F Franco and R Ferreira and E Paz and S Cardoso and P M Ramos and M Piedade and P P Freitas

    Improved Magnetic Tunnel Junctions Design for the Detection of Superficial Defects by Eddy Currents Testing Journal Article

    IEEE Trans. Magn, 50 (11), pp. 6201304, 2014.

    Links | BibTeX

    X Q Bao and R Ferreira and E Paz and D Leitao and A Silva and S Cardoso and P P Freitas and L F.Liu

    Ordered arrays of tilted silicon nanobelts with enhanced solar hydrogen evolution performance Journal Article

    Nanoscale, 6 , pp. 2097-2101, 2014.

    BibTeX

    A Roldán and J B Roldán and C Reig and S Cardoso and F Cardoso and R Ferreira and P P Freitas

    An in-depth noise model for giant magnetoresistance current sensors for circuit design and complementary metal–oxide–semiconductor integration Journal Article

    Journal of Applied Physics, 115 (17), pp. 17E514, 2014.

    Links | BibTeX

    S Cardoso and D C Leitao and L Gameiro and F Cardoso and R Ferreira and E Paz and P P Freitas

    Magnetic tunnel junction sensors with pTesla sensitivity Journal Article

    Microsyst. Technol., 20 , pp. 793-802, 2014.

    BibTeX

    Z Hou and A Silva and D C Leitao and R Ferreira and S Cardoso and P P Freitas

    Micromagnetic and magneto-transport simulations of nanodevices based on MgO tunnel junctions for memory and sensing applications Journal Article

    Physica B: Condensed Matter, 435 , pp. 163-167, 2014.

    Links | BibTeX

    D W Guo and F A Cardoso and R Ferreira and E Paz and S Cardoso and P P Freitas

    MgO-based magnetic tunnel junction sensors array for non-destructive testing applications Journal Article

    J. Appl. Phys., 115 , pp. 17E513, 2014.

    Links | BibTeX

    F A Cardoso and L Rosado and R Ferreira and E Paz and S Cardoso and P M Ramos and M Piedade and P P Freitas

    Magnetic tunnel junction based eddy current testing probe for detection of surface defects Journal Article

    J. Appl. Phys., 115 (17), pp. 15E16, 2014.

    Links | BibTeX

    D C Leitao and A Silva and R Ferreira and E Paz and F L Deepack and S Cardoso and P P Freitas

    Linear nanometric tunnel junction sensors with exchange pinned sensing layer Journal Article

    J. App. Phys., 115 (17), pp. 17E526, 2014.

    Links | BibTeX

  • 2013

    E Paz and S Serrano-Guisan and R Ferreira and P P Freitas

    Room temperature direct detection of low frequency magnetic fields in the 100 pT/Hz(0.5) range using large arrays of magnetic tunnel junctions Journal Article

    J. App. Phys., 115 (17), pp. 17E501, 2013.

    Links | BibTeX

    A Silva and D Leitao and Z Huo and R Macedo and R Ferreira and E Paz and F L Deepak and S Cardoso and P P Freitas

    Switching Field Variation in MgO Magnetic Tunnel Junction Nanopillars: Experimental Results and Micromagnetic Simulations Journal Article

    IEEE Trans. Magn, 49 (7), pp. 4405-4408, 2013.

    BibTeX

    A Lopes and S Cardoso and R Ferreira and E Paz and F L Deepak and J Sanchez and D Ramirez and S Ravelo and P P Freitas

    MgO Magnetic Tunnel Junction Electrical Current Sensor With Integrated Ru Thermal Sensor Journal Article

    IEEE Trans. Magn, 49 (7), pp. 3866-3869, 2013.

    Links | BibTeX

    J Amaral and V Pinto and T Costa and J Gaspar and R Ferreira and E Paz and S Cardoso and P P Freitas

    Integration of TMR Sensors in Silicon Microneedles for Magnetic Measurements of Neurons Journal Article

    IEEE Trans. Magn, 49 (7), pp. 3515-3515, 2013.

    Links | BibTeX

    S Cardoso and L Gameiro and D C Leitao and F Cardoso and R Ferreira and E Paz and P P Freitas and U Schmid and J Aldavero and M LeesterSchaede

    Magnetic tunnel junction sensors with pTesla sensitivity for biomedical imaging Journal Article

    Smart Sensors, Actuators, and Mems, pp. 8763, 2013.

    Links | BibTeX

    F Delgado and K Lopez and R Ferreira and J Fernández-Rossier

    Intrinsic Spin Noise in MgO Magnetic Tunnel Junctions Journal Article

    Appl. Phys. Lett., 102 (63102), 2013.

    Links | BibTeX

    N Liebing and S Serrano-Guisan and P Krzysteczko and K Rott and G Reiss and J Langer and B Ocker and H W Schumacher

    Tunneling magneto thermocurrent in CoFeB/MgO/CoFeB based magnetic tunnel junctions Journal Article

    Applied Physics Letters, 102 (24), pp. 242413, 2013.

    Links | BibTeX

  • 2012

    S Arias and D Munoz and J Moreno and S Cardoso and R Ferreira and P P Freitas

    Fractional Modeling of the AC Large-Signal Frequency Response in Magnetoresistive Current Sensors Journal Article

    Sensors, 13 (12), pp. 17516-17533, 2012.

    Links | BibTeX

    J Ventura and J M Teixeira and E Paz and J S Amaral and J D Costa and J P Araujo and S Cardoso and R Ferreira and P P Freitas

    The influence of annealing on the bimodal distribution of blocking temperatures of exchange biased bilayers Journal Article

    Phys. Status Solidi RRL, 7 (9), pp. 676-680, 2012.

    BibTeX

    R Ferreira and E Paz and P P Freitas and J Wang and S Xue

    Large Area and Low Aspect Ratio Linear Magnetic Tunnel Junctions with a Soft-Pinned Sensing Layer Journal Article

    IEEE Trans. Magn, 48 (11), pp. 3719, 2012.

    Links | BibTeX

    R Ferreira and E Paz and P P Freitas and J Ribeiro and J Germano and L Sousa

    2-axis Magnetometers Based on Full Wheatstone Bridges Incorporating Magnetic Tunnel Junctions Connected in Series Journal Article

    IEEE Trans. Magn, 48 (11), pp. 4107, 2012.

    Links | BibTeX

    J Sanchez and D Ramirez and S Ravelo and A Lopes and S Cardoso and R Ferreira and P P Freitas

    Electrical Characterization of a Magnetic Tunnel Junction Current Sensor for Industrial Applications Journal Article

    IEEE Trans. Magn, 48 (11), pp. 2823, 2012.

    Links | BibTeX

    R J Janeiro and L Gameiro and A Lopes and S Cardoso and R Ferreira and E Paz and P P Freitas

    Linearization and Field Detectivity in Magnetic Tunnel Junction Sensors Connected in Series Incorporating 16nm-thick NiFe Free Layers Journal Article

    IEEE Trans. Magn, 48 (11), pp. 4111, 2012.

    Links | BibTeX

GROUP LEADER

ricardo_ferreira_web

THE TEAM

Alex Jenkins
Staff Researcher

Elvira Paz
Staff Researcher

Tim Böhnert
Staff Researcher

Leandro Martins
Research Fellow

Luana Benetti
Research Fellow

Marcel Claro
Research Fellow

Previous Members

Lara San-Emeterio

Diogo Costa
Moved to IMEC after working at INL during 2013-2017

Bertrand Lacoste
Moved to Champalimaud after working at INL during 2013-2015

Mohammad Tarequzzaman
Moved to Analog Devices after working at INL during 2013-2018

Santiago Serrano-Guisan
Moved to Headway after working at INL during 2013-2015

RSS Latest Publications

RESEARCH