LOW-TEMPERATURE MAGNETIZATION OF MN(CH3COO)2.4H2O

Magnetization isotherms in fields up to 15 kOe have been measured at temperatures between 1.5 and 4.2°K for monoclinic single crystals of manganous acetate tetrahydrate. Continuous, quasistatic isotherms were obtained with the field along three orthogonal axes a, b, and c′. Below the zero-field transition temperature of 3.18°K, the isotherms for Ha exhibit an abrupt, perhaps discontinuous, rise at field <5 Oe, and saturate at about (53)μB•(Mn++ion). With Hb and Hc′, essentially the same saturation moment was found, but no threshold effect. The magnitude of the saturation moment is consistent with a ferrimagnetic arrangement of Mn++ moments (S=52, g=2) on two kinds of inequivalent lattice sites in the ratio 2:1. The threshold effect suggests, however, that the system combines metamagnetic properties with those of ferrimagnetism. © 1969 The American Physical Society.