Physical Review B vol:62 issue:18 pages:12241-12246
Low-temperature nuclear orientation experiments on radioactive Mn-56 ions implanted into insulating, antiferromagnetic crystals of MnCl2. 4H(2)O and CoCl2. 6H(2)O are reported. In MnCl2. 4H(2)O, comparison of the gamma -ray anisotropy of the Mn-56 nuclei with that of Mn-54, doped into the sample during growth, showed that both the Mn-56 and Mn-54 spins felt a Very similar hyperfine field. The site occupancy factor in a simple, two-site model was deduced to be 0.96(-0.07)(+0.4). In CoCl2. 6H(2)O, the average hyperfine field for the implanted Mn-56 was significantly less than that for Mn-54 and corresponded to f= 0.53+/-0.10.