Dilution dependence of blocking temperature distribution in the exchange bias system CoO(111)/Co(111)

TL;DR

This study investigates how the distribution of blocking temperatures in CoO/Co bilayers depends on dilution and how it relates to antiferromagnetic domain sizes, revealing that defects broaden the distribution and enhance exchange bias.

Contribution

It introduces a method to correlate blocking temperature distribution with domain size distribution in epitaxial CoO/Co bilayers, highlighting the effect of defects.

Findings

Broadened blocking temperature distribution due to defects.

Enhanced exchange bias field from domain size broadening.

Correlation between domain size distribution and blocking temperatures.

Abstract

In epitaxially grown CoO(111)/Co(111) bilayers we have determined the blocking temperature distribution f(Tb), which is correlated with the antiferromagnetic domain size (z) distribution f(z). The latter is probed by reversing antiferromagnetic domains at successively higher temperatures in the reversed cooling field. The implementation of nonmagnetic defects throughout the antiferromagnet CoO is found to give rise to a broadening of the domain size distribution f(z) within CoO as evidenced by a broadened f(Tb). This broadening is responsible for an enhancement of the exchange bias field.