MnCu$_{4}$In: a new high temperature ferromagnet

The new intermetallic compound MnCu$_{4}$In has been synthesized and investigated. The crystal structure, studied by single crystal and powder X-ray diffractions, shows that the compound crystallizes into its own hexagonal prototype (\textit{hP}12-$P$6$_{3}$\textit{mc}) derived from the MgZn$_{2}$-type. The measured magnetic and physical properties indicate that, in contrast to the antiferromagnetic MnCu$_{4}$Sn (MgCu$_{4}$Sn-type), MnCu$_{4}$In is a high temperature ferromagnet with $T_{C}$ = 540$^{\circ}$C. In order to understand the physics involved, the first principles calculations have been performed and compared with the MnCu$_{2}$Al-type MnCu$_{2}$In(Sn) phases and the rare earth representatives GdCu$_{4}$In and GdCu$_{2}$In. Work partially supported by the US DOE, Division of Materials Science and Engineering (Office of Basic Energy Sciences).