NUCLEAR-SPIN-LATTICE RELAXATION OF CO NUCLEI IN A FE CO MULTILAYER ATLOW-TEMPERATURES/

Low-temperature nuclear orientation has been applied to the study of t he nuclear spin-lattice relaxation (SLR) of Co-60 in the Co phase of a single-crystalline [Co(21 Angstrom)/Fe(24 Angstrom)](25) multilayer. The Co layers previously were shown to follow the bcc structure of Fe. The hyperfine field (B-hf) distribution was studied by NMR on Co-59 i n the same sample. We applied the thermal cycling (TC) method at tempe ratures around 9 mK in the external magnetic field (B-ext) range 0.05 - 1 T to determine the SLR, which was found for Co in bcc Co to be abo ut seven times faster than the SLR of Co in Fe. Moreover, the (B-ext) dependence of the SLR as observed for impurities in Fe and Co in fee C o was not found.