Phase stability and magnetic properties of the Heusler alloy Mn2CuAl ribbons

A new Mn-based Heusler alloy Mn2CuAl has been synthesized by the melt-spinning method. It has an ordered bcc structure and is a ferrimagnet with a saturation moment of 1.44 µB/f.u. at 5 K. The magnetization mainly comes from the contributions of the antiparallel aligned Mn spin moments. A compensation point is observed at 630 K, indicating the antiferromagnetism between the two Mn sublattices. The Curie temperature of the ribbons is 690 K. When heated to 740 K, the Mn2CuAl ribbons completely decompose to a mixture of a tetragonal phase and a Cu9Al4 phase.