Polarized Neutron Reflectometry Study of Depth Dependent Magnetization Variation in Co Thin Film on a PMN-PT Substrate

TL;DR

This study uses polarized neutron reflectometry to analyze how electric field-induced strain affects the depth-dependent magnetization profile in a Co thin film on a PMN-PT substrate, revealing non-uniform magnetization variations.

Contribution

It demonstrates the impact of electric field-induced strain on the depth-dependent magnetization profile in a magnetostrictive Co film, combining experimental neutron reflectometry with finite element analysis.

Findings

Electric field induces strain that rotates magnetization via the Villari effect.

Magnetization profile is non-uniform at low magnetic fields.

Strain profile correlates with depth-dependent magnetization variations.

Abstract

We studied the depth dependent magnetization profile of the magnetostrictive Co thin film layer in a PMN-PT (011)/Ta/Co/Ta structure under both zero and nonzero applied electric field using polarized neutron reflectometry. Application of electric field across the PMN-PT substrate generates a strain, which rotates the magnetization of the Co layer consistent with the Villari effect. At low magnetic fields (near remanence and coercive field conditions), we find that the depth dependent magnetization profile is non-uniform, under both zero and nonzero applied electric fields. These variations are attributable to the depth dependent strain profile in the Co film, as determined by finite element analysis simulations.