Magnetic properties of half-metallic semi Heusler Co1-xCuxMnSb compounds

A study of the half-metallic character of the semi Hensler alloys Co1-xCuxMnSb (0 <= x <= 0.9) is presented. We investigated the saturation magnetization M-S at temperatures from 5 K to room temperature and the temperature dependence of the DC magnetic susceptibility y above Curie temperature T-C. The magnetic moments at 5 K, for most compositions are very close to the quantized value of 4 mu(B) for Mn3+ ion, the compound with 90% Co substituted by Cu is still ferromagnetic with M-S (5K) = 3.78 mu(B)/f.u. These results emphasize the role of Co atoms in maintaining the ferromagnetic order in the material. The Curie temperature is decreased from 476 K to about 300 K as the Cu content increases from 0% to 90%. Above T-C, the chi(-1) vs T curves follow very well the Curie-Weiss law. The effective moment mu(eff) and paramagnetic Curie temperature theta are derived. A comparison between the values of M-S at 5 K and mu(eff) shows a transition from localized to itinerant spin system in these compounds. (C) 2006 Elsevier B.V. All rights reserved.