Hydrogen-modulated magnetism in palladium-based nanostructures for sensing and reversible control of spintronic devices

Hydrogen plays a pivotal role in the transition to renewable energy, driving the need for advanced sensing and storage technologies. Beyond its chemical reactivity, hydrogen directly modulates magnetic behavior in nanostructured materials, offering a unique avenue for multifunctional device design. Palladium-based magnetic nanostructures, particularly those incorporating cobalt, have emerged as promising platforms for hydrogen detection in spintronic applications. This review elucidates how hydrogen absorption—via palladium hydriding and Co-Pd hybridization-alters electronic structure and magnetic interactions at the nanoscale. We detail the hydrogen-induced modulation of key magnetic properties, including the Magneto-Optical Kerr Effect, coercivity, remanence, spin reorientation transitions, interlayer coupling, exchange bias, and magnetoresistance. These changes are driven by hydrogen-mediated shifts in magnetic anisotropy (MA) energy and spin texture, which are amplified in engineered nanostructures. Such materials not only enable precise monitoring of hydrogen diffusion but also serve as tunable platforms for probing perpendicular MA. By establishing a direct correlation between hydrogenation and magnetic response, this review identifies new strategies for designing hydrogen-sensitive spintronic devices. These insights pave the way for integrating hydrogen-responsive magnetic materials into next-generation technologies for clean energy, intelligent sensing, and spin-based information processing.