First-principles study of the half-metallic and magnetic properties for new yttrium-based full-Heusler alloys Y2CrZ (Z = Al, Ga, In)

First-principles calculations have been performed on the structural, electronic and magnetic properties of new yttrium-based full-Heusler alloys Y2CrZ (Z = Al, Ga, In) in Hg2CuTi structure. For three Y2CrZ (Z = Al, Ga, In) alloys, the ferromagnetic states are the most favorable states among the possible magnetic configurations. At equilibrium lattice constants of 7.079, 6.979 and 7.212 Å, the Y2CrZ (Z = Al, Ga, In) alloys are half-metallic ferromagnets with spin-up band gaps of 0.622, 0.652 and 0.489 eV, respectively. The formation energies and the cohesion energies indicate the stability of the Y2CrZ (Z = Al, Ga, In) alloys. The much higher Curie temperatures TC of 772.947, 842.512 and 966.184 K than room temperature show the Y2CrZ (Z = Al, Ga, In) alloys are suitable for spintronics and magnetoelectronics applications. The origins of the spin-up band gaps are attributed to the d-d hybridization (especially) and covalent hybridization. The total magnetic moments of 3 μB/f.u. for these alloys satisfy the Slater-Pauling rule Mt=18-Zt. In addition, the HM characters are kept in the lattice constants range from 6.757 to 7.501 Å, 6.716 to 7.422 Å and 6.743 to 7.585 Å for Y2CrZ (Z = Al, Ga, In) alloys, respectively.