Electric field control of magnetism in Si3N4 gated Pt/Co/Pt heterostructures

TL;DR

This study demonstrates electric field-induced changes in magnetic anisotropy and domain behavior in Si3N4 gated Pt/Co/Pt heterostructures, revealing magnetoelectric coupling influenced by substrate surface roughness and charge defects.

Contribution

It provides experimental evidence of magnetoelectric coupling in Si3N4 gated heterostructures and highlights the effects of substrate roughness and charge defects on control.

Findings

Electric field affects magnetic domain wall nucleation and fluctuation rates.

Coexistence of in-plane and out-of-plane magnetization observed.

Charge defects hinder systematic electrostatic control.

Abstract

In this work we show the presence of a magnetoelectric coupling in silicon-nitride gated Pt/Co/Pt heterostructures using X-ray photoemission electron microscopy (XPEEM). We observe a change in magnetic anisotropy in the form of domain wall nucleation and a change in the rate of domain wall fluctuation as a function of the applied electric field to the sample. We also observe the coexistence of in-plane and out of plane magnetization in Pt/Co/Pt heterostructures in a region around the spin reorientation transition whose formation is attributed to substrate surface roughness comparable to the film thickness; with such domain configuration, we find that the in-plane magnetization is more sensitive to the applied electric field than out of plane magnetization. Although we find an effective magnetoelectric coupling in our system, the presence of charge defects in the silicon nitride membranes hampers a systematic electrostatic control of the magnetization.