Multiple order spin-wave resonance in composition gradient sputtering FeCoB thin films

Shuai Du,Meihong Liu,Xiaoqi Ma,Jing Yu,Derang Cao,Shandong Li,Qiuyue Li,Xiaowen Chen,Jie Xu,Xinfang Guo,Yawen Song,Fanghzou Wang

doi:10.1063/5.0050965

Abstract

FeCoB films with different B doping contents and different thicknesses were deposited by composition gradient sputtering. The results show that in-plane anisotropy fields and exchange constants change with the increasing B contents and increasing thickness, respectively. Both results of the composition-gradient films and the thickness-dependent films and the micromagnetic simulation indicate that multiple order spin-wave resonances are easy to obtain in the films with the large in-plane anisotropy field. We observed four resonance peaks including three perpendicular standing spin waves. The hysteresis loop and magnetic domain results indicate that such films also have good magnetic softness and an in-plane homogeneous domain structure.

Highlights

The results show that the resonance frequency and the number of the perpendicular standing spin waves (PSSWs) can be tuned by the composition of the B element and the thickness of the film
The f r of ferromagnetic resonance (FMR) mode is determined by the saturation magnetization 4πMs and in-plane uniaxial anisotropy field Hk, while for the fr of PSSW mode, except for the contribution from 4πMs and Hk, it is related to the current order n and the exchange interaction
We can observe that all the films with different thicknesses present clear FMR mode, and the PSSW modes change with the increasing film thickness

Summary

Introduction

Both results of the composition-gradient films and the thickness-dependent films and the micromagnetic simulation indicate that multiple order spin-wave resonances are easy to obtain in the films with the large in-plane anisotropy field.

Results

Conclusion