Structure and physical properties of ternary ordered phases CuMPt6 with M = 3d elements

Measurements were made of in situ X-ray diffraction, electrical resistivity, and magnetic susceptibility for a series of newly found ternary alloys CuMPt6 with M = Ti, V, Cr, Mn, Fe, Co, and Ni. They possess, after appropriate heat treatment, the Cu3Au-type ordered structure, though the ordering is not complete for M = Ni. They are fairly good electrical conductor with a specific resistivity of around 6 × 10–3 ohm m. A general trend has been found in the magnetic property: nonmagnetic–spin-glass-like–ferromagnetic–paramagnetic, with increasing atomic number of M.The alloy with M = Mn, however, is specific among the seven alloys in that it undergoes secondary ordering into the cubic ABC6-type structure and is regarded as a counterpart of the Heusler alloy forming in the bcc systems.