Exchange bias and training effect in an amorphous zinc ferrite/ nanocrystalline gallium ferrite bilayer thin film

TL;DR

This study reports a significant exchange bias effect in an amorphous zinc ferrite/nanocrystalline gallium ferrite bilayer thin film, with temperature-dependent behavior and a training effect, highlighting interfacial spin interactions.

Contribution

It demonstrates the occurrence of exchange bias and training effects in a novel amorphous/nanocrystalline ferrite bilayer, with detailed analysis of temperature dependence and spin relaxation.

Findings

Large exchange bias (~418 Oe at 2 K) observed.

Exchange bias decreases exponentially with temperature and vanishes above 30 K.

Training effect follows spin configurational relaxation model.

Abstract

In this paper I report, exchange bias effect in a bilayer thin film of amorphous zinc ferrite and nanocrystalline gallium ferrite. The amorphous zinc ferrite layer was deposited at room temperature (Ts = RT) on top of a nanocrystalline gallium ferrite thin film using a pulsed laser. This bilayer film showed large exchange bias effect (He ~ 418 Oe at 2 K). The exchange bias shift decreased exponentially as the temperature increased and disappeared for T > 30 K. Along with the exchange bias shift the film also showed enhanced magnetization in Field Cooled (FC) measurements as compared to the Zero Field Cooled (ZFC) magnetization. The bilayer film also showed training effect at 2 K, which followed spin configurational relaxation model. The observed exchange bias effect could be attributed to the pinning anisotropy of the spin glass amorphous zinc ferrite layer pinned at the interface of gallium ferrite.