HYPERFINE INTERACTIONS AND MOSSBAUER LATT ICE TEMPERATURES FOR DOPINGSN-119(II) AND SN-119(IV) ATOMS IN AN ANTIFERROMAGNETIC SULFIDE, ALPHA-MNS

Magnetic hyperfine fields transferred at Sn-119 probe atoms (in both S n(II) and Sn(IV) valence states) in antiferromagnetic alpha-MnS have b een for the first time investigated. At 6 K, a unique hyperfine splitt ing pattern (H = 27 kOe) was observed for the Sn(II) substituant, isov alent with Mn(II), and two for the Sn(IV) heterovalent substituant (H- 1 = 392 kOe and H-2 = 296 kOe). The charge compensation mechanism is s hown to mainly involve Mn(II) vacancy location in the vicinity of Sn(I V), the two magnetically non-equivalent surroundings of Sn(IV) being r elated to the two possible spin orientations of the missing nearest ne ighbor Mn(II). The large difference in H values observed for Sn(II) an d Sn(IV) is interpreted as an indication of the prevalent contribution of 3d-5s transfer in the spin polarization of the diamagnetic impurit y. The Mossbauer lattice temperature for the Sn(IV) probe (theta(M) = 240 K) is found to be slightly higher than for the Sn(II) one (theta(M ) = 217 K).