Effect of Mn Doping on the Magnetic and Electronic Band Properties of CoFeVAl: Experiment and Theory

Heusler alloys show varieties of interesting properties, such as half-metallic, spin-gapless semiconducting, magnetocaloric, and more^[1]. Materials, exhibiting half-metallic and spin-gapless semiconducting properties, have applications in spin-transport-based devices. Ideal half-metallic Heusler alloys exhibit a Curie temperature above room temperature. Their magnetic and electronic band properties can be modified by adjusting elemental compositions. Some Heusler alloys are not half-metallic but still show high spin polarization. We carried out an experimental and theoretical investigation of one such Heusler alloy and studied the effect of Mn doping on its magnetic and electronic band properties. The first-principle calculations indicate that CoFeVAl is ferromagnetic with 87% spin polarization. However, after replacing 50% of V with Mn (CoFeV_0.5Mn_0.5Al) spin polarization increases to 96% retaining its ferromagnetic properties. The bulk ingots of both CoFeVAl and CoFeV_0.5Mn_0.5Al were prepared using arc-melting and annealing. They both crystallized in cubic structure with slight disorder. The magnetic properties of CoFeV_0.5Mn_0.5Al are consistent with the theoretical prediction, but that of the parent compound are slightly askew. In this presentation the electron transport properties of both the samples will also be discussed. Our results show that CoFeV_0.5Mn_0.5Al has potential for spintronic applications.