The structure, magnetism, and electrical-transport properties of the Heusler alloys Co2Cr1−xFexAl(x=0.2–0.6)

We synthesize the polycrystalline Heusler compounds Co2Cr1−xFexAl(x=0.2−0.6). The x-ray diffraction patterns show A2 structure rather than L21 structure. The magnetic moment and the Curie temperature increase with increasing x. The electrical resistivity characterizes the Co2Cr1−xFexAl compounds to be not typical metals and the temperature dependence of the resistivity changes from metallic to semiconductinglike behavior with increasing Cr concentrations. We attribute the fact, which we observe for most of the compounds smaller magnetic moments than the theoretical values and the low magnetoresistance in these alloys, to the considerably high level of Co-(Cr, Fe)-type disorder.