Exchange Bias in Thin Films-An Update

The exchange bias (EB) is an effect occurring in coupled ferromagnetic/antiferromagnetic materials of diverse shapes, from core-shell nanoparticles to stacked nanostructures and thin films. The interface coupling typically results in a horizontal-often also vertical-shift of the hysteresis loop, combined with an increased coercivity, as compared to the pure ferromagnet, and the possibility of asymmetric hysteresis loops. Several models have been developed since its discovery in 1956 which still have some drawbacks and some unexplained points, while exchange bias systems are at the same time being used in hard drive read heads and are part of highly important elements for spintronics applications. Here, we give an update of new theoretical models and experimental findings regarding exchange bias phenomena in thin films during the last years, including new material combinations in which an exchange bias was found.

Automated summary

Exchange bias is an effect that occurs in coupled ferromagnetic/antiferromagnetic materials, resulting in a shift of the hysteresis loop and increased coercivity, potentially creating asymmetric hysteresis loops. Despite some drawbacks and unanswered questions in existing models, exchange bias systems are widely used in hard drive read heads and spintronics applications.