Nanocrystalline alloys with a grain size of 10 or 50nm were prepared by means of direct-current sputtering and ion-beam sputtering, respectively. The magnetic relaxation (short-range diffusion) of H was investigated. The sputter-deposited films exhibited a broad relaxation spectrum in which the temperatures of the relaxation peaks depended upon the H concentration. The topological and chemical environment of the H atom was identified by means of its characteristic relaxation behavior. In nanocrystalline alloys, the H preferentially occupied sites within grain boundaries. A comparison of the present results, with relaxation measurements of H in crystalline samples, showed that the interstitial sites which were favored by H were surrounded by either one Fe and five Pd, or two Fe and four Pd, atoms. The sites were topologically disordered.

J.Mössinger, M.Hirscher, H.Kronmüller: Philosophical Magazine B, 1996, 73[3], 503-10