The study of the thermal properties of γ-Mn from Mn-Cu alloys

The addition of small amounts of Cu to Mn stabilizes the fcc phase in Mn (γ-Mn) in a broad temperature range which is otherwise stable in a narrow limit around 1400 K. These alloys undergo an fcc-fct transition on cooling which is accompanied by an abrupt appearance of antiferromagnetism. In this paper we present specific heat and thermal expansion data of three Mn-Cu alloys containing 4.42, 6.75 and 8.55 at% Cu throughout their stability range. The specific heat data reflects the features of the structural magnetic transition and suggests a high temperature anharmonic part which is supported by the thermal expansion data.