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

Wei-Hsiang Wang^1*, Wen-Chin Lin¹, Pei-hsun Jiang¹, Yu-Song Cheng², Hwo-Shuenn Sheu²

¹Physics, National Taiwan Normal University, Taipei, Taiwan
²National Synchrotron Radiation Research Center, Hsinchu, Taiwan

* Presenter:Wei-Hsiang Wang, email:a29782860@gmail.com

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. An intriguing enhancement of the hydrogen diffusion rate due to the presence of an initial exchange bias induced by a high magnetic field is thereby discovered. MOKE images reveal complicated competitions between different magnetic anisotropies during hydrogen diffusion into the film. A new spontaneous exchange bias induced by hydrogenation is discovered in the experiment as well. Our results extend the picture of hydrogen diffusivity to the regime of magnetic and spintronic properties and enrich the design of future hydrogen sensing and storage devices.

Keywords: hydrogen, exchange bias, magneto-optic Kerr effect microscopy