Moessbauer study of the magnetic phase transformations in SnMn3N

Moessbauer measurements were performed on SnMn3N with the aim of verifying the magnetic phase transformations at 175 and 230 K and the Neel transition at 475 K as well as of seeking an explanation for the anomalous peak in magnetic susceptibility about 380 K. Moessbauer spectra were taken at several temperatures between 83 and 475 K and evaluated by a least square fitting program. Abrupt changes in the hyperfine field were found at 175, 230 and 350 K indicating first-order magnetic phase transformations at these temperatures; the 350 K transformation is certainly related to the anomaly in susceptibility. About 475 only a smooth change in the hyperfine field was found suggesting the Neel transition to be of the second order. An attempt is made to explain the relatively high hyperfine field in the cubic antiferromagnetic phase. (A.K.)