How hydrogen affects the magnetic properties of Fe-Pd films

Po-Chun Chang^1*, Li-Jie Liaw¹, Yu-Tso Liao¹, Wen-Chin Lin¹

¹Department of Physics, National Taiwan Normal University, Taipei, Taiwan

* Presenter:Po-Chun Chang, email:chang155212@gmail.com

In recent years, the hydrogen effect has been widely used in spintronic materials. However, there is no clear explanation for the relationship between the hydrogen effect and hydrogen pressure, temperature, magnetic properties, structure. In this study, the curve of hydrogen adsorption and desorption in Fe-Pd film was recorded. Hydrogen was absorbed when hydrogen pressure was above 10 mbar and desorbed when hydrogen pressure was approximately 10^–6 mbar. The magnetic moment of Fe in an Fe–Pd alloy thin film was increased through hydrogen absorption, as evidenced by the enhanced x-ray magnetic circular dichroism signal of Fe. Besides, when the film is annealed to 360K, the hydrogen effect on the magnetism will disappear, but it will not cause hydrogen desorption. Finally, we found that the amorphous Fe-Pd film is more sensitive to hydrogen than FePd (111) film. The reaction of two structures checked by XRD to hydrogen was measured by the rotatable MOKE. These results reveal the correlation between hydrogen pressure, temperature, film structure, and magnetic properties and provide a typical hydrogenation effect for magnetic Pd alloys for future applications.

Keywords: FePd, hydrogen, XMCD, Kerr microscopy, XRD