MU+SR IN THE RANDOM BOND SPIN-GLASS URH2GE2

As-cast single crystals of URh2Ge2 are heavy fermions which also behav e as random-bond spin glasses. This is unusual among compounds with a translationally invariant lattice of magnetic ions. We have carried ou t mu(+)SR experiments on a single crystal in both the as-grown and ann ealed states. Strong spin depolarization is observed when the temperat ure is lowered below 15 K, but no spontaneous precession has been foun d. Experiments in a longitudinal field showed this relaxation to be of a static origin. This indicates the presence of large and random dipo lar fields at the muon site, thus of large and randomly ordered magnet ic moments. The depolarization function can be described by a stretche d exponential, characteristic for spin glasses. Experiments with diffe rent angles between the crystalline axes and the initial mu(+) spin fa iled to show any anisotropy of the depolarization rate. Also, the effe ct of annealing (one week at 900 degrees C) is very small. (C) 1998 El sevier Science B.V. All rights reserved.