Detection of Ferromagnetic Resonance from 1 nm-thick Co

TL;DR

This study demonstrates the detection of ferromagnetic resonance in a 1 nm-thick Co film when using an amorphous Ta buffer layer, highlighting potential for magnon control in ultrathin ferromagnetic films.

Contribution

It shows that inserting an amorphous Ta buffer layer enables FMR detection in ultrathin Co films, advancing understanding of ferromagnetic properties at nanoscales.

Findings

FMR not observed on SiO2 substrate

Amorphous Ta buffer layer enables FMR detection

Implication for magnon control in ultrathin films

Abstract

To explore the further possibilities of nanometer-thick ferromagnetic films (ultrathin ferromagnetic films), we investigated the ferromagnetic resonance (FMR) of 1 nm-thick Co film. Whilst an FMR signal was not observed for the Co film grown on a SiO2 substrate, the insertion of a 3 nm-thick amorphous Ta buffer layer beneath the Co enabled the detection of a salient FMR signal, which was attributed to the smooth surface of the amorphous Ta. This result implies the excitation of FMR in an ultrathin ferromagnetic film, which can pave the way to controlling magnons in ultrathin ferromagnetic films.