FIELD-INDUCED MAGNETIC TRANSITION OF MN3GAC

Field-induced transitions were studied in Mn3GaC in magnetic fields up to 370 kOe. The antiferromagnetic (AFM)-ferromagnetic (FM) field-indu ced transition is of the first order. The saturation magnetization sig ma(s) at 4.2 K in the FM state is 75.0 emu g(-1) equivalent to 1.1 mu( B) per Mn atom. The decreasing rate of sigma(s) is rather smaller than that of the S = 1/2 Brillouin function. In the magnetostriction measu rement of Mn3GaC, an abrupt volume contraction of -0.50% was found at the AFM-FM transition temperature. The result of the forced volume mag netostriction measurement shows that sigma(s) at 4.2 K increases with pressure. (C) 1997 Elsevier Science Ltd.