Localized Magnetic Moments in Mn₄N

Abstract

The temperature dependence of sublattice magnetizations and the specific heat due to magnetic ordering of Mn₄N were measured in order to study the origin of the anomalous thermomagnetic curve of the compound. The observed magnetization-temperature curves of two sublattices are more convex upwards than those of normal magnetic crystals. The discontinuity of specific heat at the Curie temperature was found to be 7.4±1.0 cal/formula deg. which is much smaller than that expected on the assumption that the localized magnetic moments remain unchanged up to high temperatures. The average state density at the Fermi surface was estimated from the temperature independent magnetic susceptibility to be about 6/Mn eV. It was concluded from these facts that the high state density gives rise to large induced moments at low temperatures which depolarize with increasing temperature.