Alex Jenkins

Staff researcher

Alex finished both his undergraduate (MPhys) and postdoctoral (PhD) studies at the University of Leeds, which focused on the unconventional proximity effect in superconductor/ferromagnet hetereostructures. He then moved to Spintec labs in Grenoble where he performed the high frequency characterization of a range of magnetic systems, including in-plane and out-of-plane magnetic layers and coupled synthetic antiferromagnetic layers for both GMR spin valves and MgO based magnetic tunnel junctions. In order to fully understand the dynamical behavior of these systems, measurements in both the frequency and time domain were performed at both room temperature and low temperatures.
Alex then moved to CNRS/Thales in Palaiseau, France, where he focused on the use of vortex oscillators as a potential high frequency detector. They showed that when excited by an rf frequency current, the vortex will be excited to very large orbit radii, which can be used to switch the chirality and polarity of the vortex, and even to remove the vortex completely from the free layer, an effect shown to be the basis of a highly efficient threshold detector.
Alex started as a staff researcher at INL in March 2016, focusing on the high frequency characterization of magnetic tunnel junction based spin torque oscillators. He is in charge of the high frequency measurement lab, and is focused on the development of magnetic vortex-based oscillators for a range of applications, including frequency generators, detectors, energy harvesting and neuromorphic computing architectures.

Selected Publications

  • Spin torque resonant vortex core expulsion for an efficient radio-frequency detection scheme, A. S. Jenkins et al. Nat. Nanotech. 11, 360–364 (2016)
  • Controlling the chirality and polarity of vortices in magnetic tunnel junctions, A. S. Jenkins, et al., Applied Physics Letters, 105, 17, (2014)
  • Understanding of Phase Noise Squeezing Under Fractional Synchronization of a Nonlinear Spin Transfer Vortex Oscillator, R. Lebrun, ASJ et al., Phys. Rev. Lett. 115, 017201 (2015).
  • Current driven magnetization dynamics of a self-polarised synthetic ferrimagnet, A. S. Jenkins, et al., Journal of Applied Physics, 15, 8 (2014)
  • Mutual synchronization of spin torque nano-oscillators through a long-range and tunable electrical coupling scheme, R. Lebrun, ASJ et al., Nat. Comm. (2017).