Unusual field dependence of remanent magnetization in granular CrO2: possible role of piezomagnetism

TL;DR

This study investigates the unusual low-field remanent magnetization behavior in granular CrO2 and Cr2O3 composites, suggesting piezomagnetism in the antiferromagnetic component influences the ferromagnetic remanence.

Contribution

It reveals a novel field-dependent remanent magnetization behavior linked to piezomagnetism in granular CrO2 composites, a phenomenon not previously characterized in this context.

Findings

TRM exhibits two distinct time scales.

Remanence first increases then decreases with cooling field.

Piezomoments in AFM component influence FM dynamics.

Abstract

We present low field thermoremanent magnetization (TRM) measurements in granular CrO2 and composites of ferromagnetic (FM) CrO2 and antiferromagnetic (AFM) Cr2O3. TRM in these samples is seen to display two distinct time scales. A quasi static part of remanence, appearing only in low field regime exhibits a peculiar field dependence. TRM is seen to first rise and then fall with increasing cooling fields, eventually vanishing above a critical field. Similar features in TRM have previously been observed in some antiferromagnets that exhibit the phenomenon of piezomagnetism. Scaling analysis of the TRM data suggest that presumably piezomoments generated in the AFM component drive the FM magnetization dynamics in these granular systems in low field regime.