Influence of mixing the low-valent transition metal atoms Y = Sc, Ti, V, Cr, Mn and Fe on the properties of possible half-metallic Heusler compounds Co_1.5Y_0.5FeSi

The realization of physical systems whose electronic and magnetic properties can be easily manipulated by playing with valence electrons are very promising from both the fundamental and applied perspectives. Half-metallic ferromagnets with high T_c are ideal candidates for spintronic applications. Co- based Heusler alloys have recently attracted great interest because most of these alloys exhibit above mentioned criteria. Here, we present a combined experimental and theoretical study of quaternary Heusler alloys Co_1.5Y_0.5FeSi (Y = Sc,Ti,V,Cr,Mn,&Fe) to get a global overview of the electronic, magnetic and mechanical properties. All single phase alloys exhibit fcc crystal structure with a strong tendency towards L2₁ ordering. The low-temperature saturation magnetic moments agree fairly well with our theoretical results and also obey the Slater-Pauling rule, a prerequisite for half metallicity¹. All alloys are soft ferromagnets with high T_c, allowing for applications at room temperature and above. Relatively high mechanical hardness values are also observed^1,2,3.

References:
1. KC et al., Phys. Rev. Materials 3, 114406(2019)
2. Mahat et al., Journal of Alloys and Compounds, 154403 (2020)
3. Mahat et al., Journal of Magnetism and Magnetic Materials, 167398 (2020)