Spintronics studies phenomena associated with spins – intrinsic angular momentum inherent to electrons and other elementary particles and quasiparticles. Spin is most commonly transported through translational motion of electrons, which might or might not be accompanied by charge transport. Alternatively, spin can be carried via wave motion of localised spins – so-called spin waves – in a process analogous to the transmission of energy by oscillating charges in ac electrical circuits.
Spintronics-based technology is already used in magnetic hard disk drives, where the magneto-resistive sensors are used to read out recorded information. It is also in the heart of magnetic (MRAM) and spin-transfer-torque (STT-RAM) random access memory elements, undergoing last stages of their development. In other developments, spin-based devices may serve as on-chip microwave sources and form the most promising platform for realisation of neuromorphic and quantum computers.
At Exeter, we investigate high-frequency and ultrafast spintronic phenomena, using experiments, numerical simulations and analytical theory. The focus of our current research is on:
- Optically induced ultrafast spin and magnetisation dynamics and relaxation ;
- High-frequency properties of magneto-resistive and spin-torque devices ;
- Detection and imaging of electrically and thermally induced spin currents, spin-caloritronics ;
- Cavity-opto-spintronics and magneto-photonics .
- V. V. Kruglyak, R. J. Hicken, M. Ali, B. J. Hickey, A. T. J. Pym, and B. K. Tanner, “Measurement of hot electron momentum relaxation times in metals by femtosecond ellipsometry”, Phys. Rev. B 71, 233104 (2005).
- P. S. Keatley, S. R. Sani, G. Hrkac, S. M. Mohseni, P. Durrenfeld, J. Akerman, and R. J. Hicken, “Superharmonic injection locking of nanocontact spin-torque vortex oscillators”, Phys. Rev. B 94, 094404 (2016).
- J. Li et al, “Direct Detection of Pure ac Spin Current by X-Ray Pump-Probe Measurements”, Phys. Rev. Lett. 117, 076602 (2016).
- R. R. Subkhangulov, R. V. Mikhaylovskiy, A. K. Zvezdin, V. V. Kruglyak, T. Rasing, and A. V. Kimel, “Terahertz modulation of the Faraday rotation by laser pulses via the optical Kerr effect”, Nature Photonics 10, 111 (2016).