Manipulating the magnetic anisotropy and magnetization dynamics by stress: Numerical calculation and experiment

M.A Correa,F Bohn

doi:10.1016/j.jmmm.2017.12.087

Abstract

We perform a theoretical and experimental investigation of the magnetic properties and magnetization dynamics of a ferromagnetic magnetostrictive multilayer grown onto a flexible substrate and submitted to external stress. We calculate the magnetic behavior and magnetoimpedance effect for a trilayered system from an approach that considers a magnetic permeability model for planar geometry and a magnetic free energy density which takes into account induced uniaxial and magnetoelastic anisotropy contributions. We verify remarkable modifications of the magnetic anisotropy with external stress, as well as we show that the dynamic magnetic response is strongly affected by these changes. We discuss the magnetic features that lead to modifications of the frequency limits where distinct mechanisms are responsible by the magnetoimpedance variations, enabling us to manipulate the resonance fields. To test the robustness of the approach, we directly compare theoretical results with experimental data. Thus, we provide experimental evidence to confirm the validity of the theoretical approach, as well as to manipulate the resonance fields to tune the MI response according to real applications in devices.

Highlights

Magnetoelastic properties in thin films and multilayers have attracted increasing attention in recent decade due to a wide variety of applications in magnetic memory elements [1,2,3] and acoustic generation of resonant spin-wave excitations [4,5]
We report a theoretical and experimental investigation of the magnetic properties and magnetization dynamics of a ferromagnetic magnetostrictive multilayer grown onto a flexible substrate and submitted to external stress
We verify remarkable modifications of the magnetic anisotropy with external stress, as well as we show that the dynamic magnetic response is strongly affected by these changes

Summary

Introduction

Magnetoelastic properties in thin films and multilayers have attracted increasing attention in recent decade due to a wide variety of applications in magnetic memory elements [1,2,3] and acoustic generation of resonant spin-wave excitations [4,5]. Magnetostrictive films and multilayers grown onto flexible substrates appears as remarkable candidates as ground for spintronic devices, mainly due to the manipulable magnetic and mechanical properties [6,7,8]. This explains the recent interest in controlling and handling of properties as magnetic anisotropy, dynamic magnetic response, magnetostrictive properties and stress in ferromagnetic flexible nanostructures. Irrespective on the future technological application, the study of the electrical and magnetic properties of magnetostrictive films and multilayers grown onto flexible substrates is essential In this context, the comprehension of the mechanisms that control the magnetization dynamics is of fundamental importance to understand the basic physical. We discuss the magnetic features that lead to modifications of the frequency limits where distinct mechanisms are responsible by the MI variations, enabling us to manipulate the resonance fields to tune the MI response according to real applications in devices

Numerical calculation

Comparison with the experiment

Conclusion