Thickness dependence of the exchange bias in epitaxial manganite bilayers

TL;DR

This study investigates how the exchange bias effect in epitaxial manganite bilayers varies with the thickness of the antiferromagnetic layer, revealing a critical threshold and quantifying anisotropy.

Contribution

It provides the first detailed analysis of thickness dependence of exchange bias in high-quality epitaxial manganite bilayers, including a critical thickness and anisotropy constant.

Findings

Identified a critical thickness for exchange bias onset.

Quantified the antiferromagnetic anisotropy constant.

Confirmed high crystalline quality of the bilayers.

Abstract

Exchange bias has been studied in a series of La2/3Ca1/3MnO3 / La1/3Ca2/3MnO3 bilayers grown on (001) SrTiO3 substrates by ozone-assisted molecular beam epitaxy. The high crystalline quality of the samples and interfaces has been verified using high-resolution X-ray diffractometry and Z-contrast scanning transmission electron microscopy with electron energy loss spectroscopy. The dependence of exchange bias on the thickness of the antiferromagnetic layer has been investigated. A critical value for the onset of the hysteresis loop shift has been determined. An antiferromagnetic anisotropy constant has been obtained by fitting the results to the generalized Meiklejohn-Bean model.