Investigation of the magnetic hyperfine field at the Y site in the Heusler alloys Co(2)Y(1-x)(1)Y(x)(2)Z (Y=Ti, V, Nb,Cr; Z=Al, Sn)

The magnetic hyperfine field (mhf) acting on a Ta-181 probe dilutely substituted at the non-magnetic transition element site has been investigated for the pseudo-quaternary Heusler alloys Co2Ti1-xNbxAl, Co2Ti1-xVxAl, Co2Ti1-xVxSn, and Co2V1-xCrxAl with x = 0.2,0.4,0.6 and 0.8 by TDPAC measurements utilizing the 133-482 keV gamma-gamma cascade in Ta-181 following the beta(-)-decay of Hf-181. Magnetization measurements on Co2Ti1-x(Nb, V)(x)Al samples were carried out by using a vibrating-sample magnetometer. The Curie temperature and the saturation magnetization were obtained for each alloy. The lattice parameters of the alloys were determined by x-ray diffraction measurements. The results for the mhf acting on Ta occupying the non-magnetic transition element site are discussed and compared with the mhf systematics for the cobalt-based Heusler alloys.