Exchange-bias dependent diffusion rate of hydrogen discovered from evolution of hydrogen-induced noncollinear magnetic anisotropy in FePd thin films

TL;DR

This study uncovers how exchange bias influences hydrogen diffusion rates in FePd thin films, revealing complex magnetic anisotropy evolution and suggesting new control mechanisms for hydrogen sensing and storage.

Contribution

It demonstrates that initial exchange bias significantly enhances hydrogen diffusion in FePd films, linking magnetic properties with hydrogen diffusion behavior.

Findings

Hydrogen induces noncollinear magnetic anisotropy in FePd films.

Exchange bias accelerates hydrogen diffusion.

Magnetic domain evolution correlates with hydrogen diffusion dynamics.

Abstract

Hydrogenation-induced noncollinear magnetic anisotropy is observed from the evolution of the magnetic domains in FePd alloy thin films using magneto-optic Kerr effect (MOKE) microscopy. MOKE images reveal complicated competitions between different magnetic anisotropies during hydrogen diffusion into the film. An intriguing enhancement of the hydrogen diffusion rate due to the presence of an initial exchange bias induced by a high magnet field is thereby discovered, pointing to an additional scope of controllability of magnetic metal hydrides as potential future hydrogen sensing and storage materials.