  In this work, we investigate the effects of H2 on the physical properties of
Fe25Pd75. Broadband ferromagnetic resonance (FMR) spectroscopy revealed a
significant FMR peak shift induced by H2 absorption for the FCC phased
Fe25Pd75. The peak shifted towards higher applied fields, which is contrary to
what was previously observed for CoPd alloys. Additionally, we conducted
structural and magneto-optical Kerr ellipsometric studies on the Fe25Pd75 film
and performed density functional theory calculations to explore the electronic
and magnetic properties in both hydrogenated and dehydrogenated states. In the
final part of this study, we deposited a Fe25Pd75 layer on top of a microscopic
coplanar transmission line and investigated the FMR response of the layer while
driven by a microwave current in the coplanar line. We observed a large
amplitude FMR response upon hydrogen absorption, as well as desorption rates
when cycling between pure N2 and a mixture of 3% H2 + 97% N2.
