CoRuFeX (X = Si and Ge) Heusler alloys: High TC materials for spintronic applications

In this paper, CoRuFeX (X = Si, Ge) alloys were investigated by means of x-ray diffraction, Mossbauer spectroscopy, magnetic and magneto-transport measurements. Alloys are found to be exist in Y-type structure with presence of some B2 disorder. High values of Curie temperature (T-C) of 867 K and 833 K are obtained for CoRuFeSi and CoRuFeGe alloys, respectively. The obtained T-C values are found to be highest among all the equiatomic quaternary Heusler alloys. The saturation magnetization (MS) values are found to be in good agreement with the values obtained from Slater-Pauling estimation, which is a prerequisite for half-metallic ferromagnets. Electrical resistivity in the temperature range of 5-300 K gives an indirect evidence of half-metallic behavior in these alloys at low temperatures. Considering high T-C and the transport behavior, both these materials seem to be interesting for spintronic applications. (C) 2015 Elsevier B.V. All rights reserved.