Spin injection into vanadium dioxide films from a typical ferromagnetic metal, across the metal-insulator transition of the vanadium dioxide films

TL;DR

This study demonstrates spin injection from a ferromagnetic metal into vanadium dioxide across its metal-insulator transition, revealing that electromotive force signals are maintained despite drastic resistance changes.

Contribution

We experimentally show spin injection into VO2 across its MIT, combining FMR and electromotive force measurements to reveal spin transport properties.

Findings

Electromotive force in VO2/Ni80Fe20 bilayer shows minimal change across MIT.

Spin injection into VO2 is confirmed despite large resistance variation.

Inverse spin-Hall effect contributes to electromotive force signals.

Abstract

A vanadium dioxide VO2 film shows metal-insulator transition (MIT) induced by changing environmental temperature. We report the temperature dependence of electromotive force properties generated in VO2/Ni80Fe20 bilayer junctions under the ferromagnetic resonance (FMR) of the Ni80Fe20 layer. An electromotive force generated in a VO2/Ni80Fe20 bilayer junction under the FMR showed a small change across the MIT temperature of the VO2 film, while the VO2 film resistance drastically changed. This behavior was not only explained with the temperature dependence of the electromotive force property generated in the Ni80Fe20 film itself under the FMR, but also with the generated electromotive forces due to the inverse spin-Hall effect (ISHE) in the VO2 film under the FMR of the Ni80Fe20 film. That is, we successfully demonstrated the spin injection from a Ni80Fe20 film into a VO2 film across the MIT temperature of the VO2 film.