Magnetic and transport properties of Co2MnSnxSb1-x Heusler alloys

We present the magnetic, structural, and transport properties of the quaternary Heusler alloys Co2MnSnxSb1-x (x=0, 0.25, 0.50, 0.75, and 1.0), which have been theoretically predicted to be half-metallic. Magnetization measurements as a function of applied field show that the saturation moment for x=1 (Co2MnSn) is near the Slater-Pauling value of 5 mu(B); however, the moment for x=0 (Co2MnSb) falls far short of its predicted value of 6 mu(B). Resistivity as a function of temperature was measured from 5 to 400 K, and a phase transition from a half-metallic ferromagnetic phase to a normal ferromagnetic phase was observed between 50 and 80 K for all of the alloys. At low temperature (10 K < T < 40 K), the resistivity ratio was found to vary as R(T)/R(T=5 K)=A +BT2+CT9/2, where the T-2 term results from electron-electron scattering, whereas the T-9/2 term is a consequence of double magnon scattering. (C) 2009 American Institute of Physics.