M\"ossbauer study of the field induced uniaxial anisotropy in electro-deposited FeCo alloy films

TL;DR

This study uses Mössbauer spectroscopy to investigate how applying an external magnetic field during electro-deposition induces uniaxial in-plane magnetic anisotropy in FeCo alloy films, revealing the atomic-level origin of the anisotropy.

Contribution

It demonstrates that external magnetic fields during electro-deposition cause directional atomic ordering, leading to in-plane uniaxial anisotropy in FeCo films, a novel insight into magnetic film fabrication.

Findings

Films deposited with external field show uniaxial anisotropy aligned with the field.

Magnetic moments are constrained in the film plane when deposited with external field.

Anisotropy arises from directional atomic pair ordering during deposition.

Abstract

Thin ferromagnetic films with in-plane magnetic anisotropy are promising materials for obtaining high microwave permeability. The paper reports on the M\"ossbauer study of the field induced in-plane uniaxial anisotropy in electro-deposited $FeCo$ alloy films. The $FeCo$ alloy films have been prepared by electro-deposition method with and without external magnetic field applied parallel to the film plane during deposition. The vibrating sample magnetometry and M\"ossbauer spectroscopy measurements at room temperature indicate that the film deposited in external field shows an in-plane uniaxial anisotropy with an easy direction coincides with the external field direction and a hard direction perpendicular to the field direction, whereas the film deposited without external field doesn't show any in-plane anisotropy. M\"ossbauer spectra taken in three geometric arrangements show that the magnetic moments are almost constrained in the film plane for the film deposited with applied magnetic field. And the magnetic moments are tend to align in the direction of the applied external magnetic field during deposition, indicating that the observed anisotropy should be attributed to directional ordering of atomic pairs.