Muon-hydrogen correlation in amorphous alloys

Abstract

Abstract Muon spin relaxation has been measured in the amorphous transition-metal alloy Zr2Pd containing a high concentration of interstitial hydrogen. The nuclear spin dipole moments of the metal atoms in this alloy are relatively small with the result that the local magnetic field at the muon arises almost entirely from the nuclear moments of the hydrogen atoms. Even at the lowest temperature of measurement, ∼ 10 K, the relaxation profiles are consistent with fluctuating local fields. The correlation time is typically a few microseconds and varies only slowly with temperature up to about 100 K. On the other hand, above 250 K, where the diffusion hopping rate of the hydrogen atoms is about 107-108 s−1 as measured by nuclear relaxation methods, the correlation times vary more rapidly with temperature and may be described in terms of activation energies which are similar to the activation energies of the hydrogen diffusion. In addition the correlation time of the local field at the muon was found to be gre...