Micromagnetic analysis of magnetization reversal in Fe77.5Si7.5B15 amorphous glass-coated nanowires

C Rotărescu,T.-A Óvári,N Lupu,H Chiriac

doi:10.1063/1.5119450

C Rotărescu, T.-A Óvári + Show 2 more

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https://doi.org/10.1063/1.5119450

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Abstract

A micromagnetic model based on the finite element method (FEM) is proposed in order to investigate the specific role of the magnetoelastic anisotropy in the axial magnetization reversal process of highly magnetostrictive amorphous glass-coated nanowires with cylindrical symmetry, prepared by means of rapid quenching from the melt. Using a radially distributed magnetoelastic anisotropy term, we demonstrate that both the magnitude and the shape of the anisotropy distribution affect the value of their nucleation field, and, in well-defined cases, of their switching field. The analysis provides a good explanation framework for the characteristics of magnetic bistability in magnetostrictive glass-coated amorphous nanowires, enhancing the potential applicability of these novel ferromagnetic amorphous nanosized materials.

Highlights

Amorphous glass-coated nanowires with cylindrical symmetry, having extremely thin metallic nuclei, have been prepared by rapid quenching from the melt in a single step process.1 They are composite wires, obtained in a single-step fabrication process, in which a cylindrical ferromagnetic nucleus – the actual magnetic nanowire – is directly quenched within an insulating glass layer
It is important to mention that only the terms in equation (2) affect the magnetization reversal process, and, the domain wall pinning is mainly a consequence of the magnetoelastic contribution, as it results from the associated changes reflected in the switching field
The performed analysis shows that the radial magnetoelastic anisotropy distribution plays a key role in the magnetic behavior of rapidly quenched amorphous glass-coated nanowires

Summary

Introduction

Amorphous glass-coated nanowires with cylindrical symmetry, having extremely thin metallic nuclei (diameters down to 90 nm), have been prepared by rapid quenching from the melt in a single step process.1 They are composite wires, obtained in a single-step fabrication process, in which a cylindrical ferromagnetic nucleus – the actual magnetic nanowire – is directly quenched within an insulating glass layer. The main characteristic of the magnetic behavior of rapidly quenched amorphous glass-coated nanowires is magnetic bistability, i.e. an axial magnetization reversal process that takes place in a single step when the applied magnetic field reaches a specific value called switching field.

Results

Conclusion