Controlling Spin-Orbit Torques through Strong Correlation

Abstract

This dissertation discusses the generation and measurement of current-induced spin-orbit torques in $4f$ orbital systems. The first three chapters lay out the intuition for understanding the later experimental results and the required experimental considerations to generate data with robust interpretations. The second half discusses the measure of current-induced spin-orbit torques in four rare earth metals (Gd, Dy, Ho, and Lu) and the way in which the presence (or absence) of $4f$ orbital derived states at the Fermi level influences the torques generated. The final chapter discuses the non-trivial temperature evolution of the torques generated by a Kondo lattice system, YbAl$_3$, in light of the understanding gained from the study of the pure rare earth materials. Ultimately, it is argued that the measurement of current-induced spin-orbit torques may be a useful analytical tool for probing the Fermi surface of $f$-valent and heavy fermion systems.