Experimental study of the structural, magnetic, electrical, and mechanical properties of possible half-metallic Co[formula omitted]V[formula omitted]FeGe Heusler alloys

Abstract

In this study, we experimentally investigated quaternary Heusler alloys Co2−xVxFeGe with 0≤x≤1 prepared by arc melting and annealing, and showed that they are promising candidates for spintronics applications. Single phase microstructures were observed for V compositions from x=0.25 to x=0.625. Other V concentrations were multi-phased. All single phase samples had a face centered cubic crystal structure with a lattice constant that increased linearly with the V concentration. The low-temperature saturation magnetic moments were shown to obey the Slater–Pauling rule of thumb for half-metals, which is a prerequisite for half metallicity. All alloys had high Curie temperatures, which scaled linearly with the saturation magnetic moment, thereby facilitating applications at room temperature and above. Electrical transport measurements were performed to elucidate the electronic structures of the alloys. The temperature dependence of the electrical resistivity was analyzed and discussed in the framework of the two-current conduction model by considering the existence of an energy gap in the electronic spectrum around the Fermi level of the spin down sub-band. High mechanical hardness values were also observed.