The effect of interface roughness on exchange bias in La0.7Sr0.3MnO3 - BiFeO3 heterostructures

TL;DR

This study investigates how interface roughness affects exchange bias in La0.7Sr0.3MnO3 - BiFeO3 heterostructures, revealing that rough interfaces induce exchange bias while sharp interfaces do not.

Contribution

It demonstrates that interface roughness and chemical intermixing are crucial for exchange bias in these heterostructures, highlighting the role of interfacial properties in magnetic coupling.

Findings

Rough interfaces exhibit sizable exchange bias.

Sharp interfaces show no detectable exchange bias.

Temperature-dependent magnetization suggests spin-glass-like behavior.

Abstract

We characterized the interfaces of heterostructures with different stack sequences of La0.7Sr0.3MnO3/BiFeO3 (LSMO/BFO) and BFO/LSMO using TEM revealing sharp and rough interfaces, respectively. Magnetometry and magnetoresistance measurements do not show a detectable exchange bias coupling for the multistack with sharp interface. Instead, the heterostructures with rough and chemically intermixed interfaces exhibit a sizable exchange bias coupling. Furthermore, we find a temperature-dependent irreversible magnetization behavior and an exponential decay of coercive and exchange bias field with temperature suggesting a possible spin-glass-like state at the interface of both stacks.