The structural transformation from metallic glass to nanostructure and improvement of the magnetic properties by using pulse annealing method (PAM)

Abstract

Improvement of the magnetic properties and structural transformation of metallic glasses can be done by using Pulse Annealing Method (PAM). The basic problems of the conventional annealing treatments are oxidation and difficulties about managing the crystallization steps. PAM overcomes these limitations and cause low coercivity in contrast to high susceptibility in milliseconds. Recent works investigated that partially nucleation, partially crystallization and nanostructure of the materials are preferable from the industrial application point of view and it is easy to approach to these advantageous by PAM. In this study, PAM was explained and schematic illustration was given. Metallic glasses Fe40Ni40B20, Fe39Ni39Mo4Si6B12 and Fe77Cr2Si5B16 were annealed by PAM. Coercivity (H-c) and susceptibility (chi) values were measured after some steps of electrical pulse application to the samples. H-c-Pulse numbers and chi-Pulse numbers plots of the samples were given. It has to be pointed out that the structures of the samples are transformed from metallic glass to nanostructure with PAM in milliseconds. Ferromagnetic resonance (FMR) studies supporting the occurrence of nanostructure by PAM treatments were also given. FMR studies of the samples show the magnetic anisotropy and improvement of it by PAM were also given.