NMR studies of an icosahedral Al72.4Pd20.5Mn7.1 quasicrystal

We report the results of Al-27 nuclear magnetic resonance studies of a sing le-grain icosahedral Al72.4Pd20.5Mn7.1 quasicrystal at low temperatures. Th e Al-NMR line width displays a broad maximum near 20 K, and a sharp anomalo us increase with decreasing temperatures near 2 K. The temperature dependen ce of the spin-lattice relaxation rate is approximately linear above 2 K, w ith (T1T)(-1) approximate to 0.02 (Ks)(-1). Below 2 K there is a qualitativ e change in the relaxation behavior, such that (T1T)(-1) increases substant ially with decreasing temperatures. Our results are interpreted as evidence for an anomalous dynamics of the magnetic moments associated with the Mn i ons. (C) 2000 Elsevier Science B.V. All rights reserved.