Electric field control of spin-charge interconversion in ferromagnetic-free oxide Rashba nanodevices
CNRS/Thales, University Paris-Saclay
Abstract: A plethora of exciting properties have been observed at the oxide heterointerface between LaAlO3 and SrTiO3. Most prominently it has been demonstrated that the confined electron gas formed at the interface features e.g. gate-tunable superconductivity, ferromagnetism and a sizeable Rashba spin-orbit coupling. This Rashba spin-orbit coupling allows a considerable charge/spin interconversion to take place at this particular interface as previously demonstrated by spin pumping ferromagnetic resonance experiments from a NiFe contact. Moreover, the efficiency of this charge-to-spin conversion was demonstrated to be strongly tunable by a gate voltage. Transport experiments of patterned LaAlO3/SrTiO3 devices have also allowed detection and quantification of this charge-to-spin conversion through non-local resistance measurements. Here, we probe spin/charge interconversion through the two-dimensional spin Hall effect in patterned amorphous-LaAlO3/SrTiO3 planar nanodevices using the Hanle effect. Specifically, we investigate the dependence of the non-local spin resistance as a function of back-gate voltage, temperature, channel length and magnetic field angle. From these measurements, we observe a large non-monotonic modulation of the spin Hall angle and characteristic spin diffusion length when the back-gate voltage is varied. Most notably, we observe a spin diffusion length of up to ~1 μm at 2 K for certain gate voltages, which compared with the spin diffusion length in e.g. Pt of ~4-5 nm at 2 K, highlights this particular oxide interface as a strong candidate for spintronic applications.
Brief Bio:
Dr. Felix Trier is a post-doctoral researcher in CNRS/Thales lab in University Paris-Saclay. He obtained his B.Sc. (2009) and M.Sc. (2012) in nanoscience at University of Copenhagen (KU) . Then he earned his Ph.D. degree (2016) at Technical University of Denmark (DTU). Dr. Trier’s current research interest mainly include the charge/spin interconversion through Rashba spin-orbit coupling at oxide heterointerfacs and the electric tuning of such nanodevices.
