Magnetostrictive devices and methods involving a magnetostrictive alloy having; (1) one or more of Pd, and Pt, and (2) one or more of Ni, Co, Fe, where the alloy comprises one or more of Pd.sub.xNi.sub.1-x, Pd.sub.xFe.sub.1-x, Pd.sub.xCo.sub.1-x, Pt.sub.xNi.sub.1-x, Pt.sub.xFe.sub.1-x, Pt.sub.xCo.sub.1-x, where x is less than 1, where magnetostrictive properties and diffusion, and solubility properties than variable in response to variations to a magnetic field to which the alloy is subjected. Devices and methods are used in hydrogen storage, isotopic separation, catalytic systems, actuator/sensor, and other magnetostrictive applications.