The Final Lecture（Dr. Yoshichika Otani）

Title

A Journey through Spintronics Research

Abstract

Over the past few decades, spintronics has evolved into a diverse field, giving rise to various subfields, including spin caloritronics, spin mechanics, spin-orbitronics, and orbitronics. At RIKEN CEMS, my research team has been exploring the fundamental spin conversion mechanisms that drive these fields, along with the magnetization dynamics associated with them. Understanding these conversion processes is essential for developing new functionalities in spintronic devices and uncovering novel physical phenomena.

In our studies, we have demonstrated the electrical detection of key spin transport phenomena, including the long-distance diffusive propagation of spins, direct and inverse spin Hall effects, Onsager’s reciprocal relations, spin-Edelstein effects, and magnetic spin Hall effects. These results have provided deeper insight into how spin currents interact with charge and orbital degrees of freedom. More recently, we have discovered that the spin conversion process can give rise to coupled quasiparticles, leading us to investigate the controlled realization of strongly coupled states. In particular, we focus on low-energy excitations involving quasiparticles such as magnons and phonons, aiming to harness their interactions for new quantum functionalities.

In this talk, I will share how my interest in magnetism led me to the field of spintronics, along with some of the key discoveries made in my laboratory and their potential implications for future research.