Giant widening of interface magnetic layer in almost compensated iron garnet

TL;DR

This study reveals a significant widening of the interface magnetic layer in a compensated iron garnet near the compensation temperature, driven by gadolinium diffusion, leading to an inhomogeneous magnetic structure.

Contribution

It demonstrates the interfacial origin of magnetic precursor phenomena and the dramatic growth of the inhomogeneous magnetic layer in a ferrimagnet near compensation temperature.

Findings

Extended inhomogeneous magnetic structure near compensation temperature

Gadolinium diffusion causes a thin intermixed layer with enhanced magnetization

Precursor shape linked to easy-plane anisotropy of the intermixed layer

Abstract

A two-sublattice ferrimagnet undergoes a transition from a collinear to canted magnetic phase at magnetic field oriented along an easy magnetization direction. In this work, we study the transition by means of the magneto-optical Faraday effect in a thin film of compensated iron garnet (Lu$_{3-{\rm{x}}}$Bi$_{\rm{x}}$)(Fe$_{5-{\rm{y}}-{\rm{z}}}$Ga$_{\rm{y}}$Al$_{\rm{z}}$)O$_{12}$ grown on Gd$_3$Ga$_5$O$_{12}$ substrate. In the immediate vicinity of the compensation temperature a precursor of the transition with a complex shape was observed. Using a special sample with variable thickness we demonstrate an interfacial origin of the precursor. Diffusion of gadolinium from the substrate into the film forms a thin intermixed layer with enhanced magnetization. It induces an extended inhomogeneous magnetic structure in the film. A two-step shape of the precursor appears due to an easy-plane anisotropy of the intermixed magnetic layer. We emphasize that an effective width of the inhomogeneous magnetization distribution in the film grows enormously while approaching the compensation temperature.