The structural, electronic, elastic, thermodynamic, magnetic, and optical properties of the yttrium-based full-Heusler alloys Y2CrZ (Z=Si, Ge, Sn)

Abstract

The structural, electronic, elastic, thermodynamic, magnetic, and optical properties of yttrium-based full-Heusler alloys of the form Y2CrZ (Z = Si, Ge, Sn) have been studied by first-principles calculations. The stable half-metallic ferrimagnetic characters, which are maintained in the lattice constant ranges 6.365–7.057 Å (Y2CrSi), 6.496–7.163 Å (Y2CrGe), and 6.515–7.385 Å (Y2CrSn), ensure their potential application in spintronics and magnetoelectronics. The total magnetic moment of 2 μB per formula unit satisfies the Slater-Pauling rule Mt=18-Zt. The formation energy Ef, cohesion energy Ec, spin-up band gap Eg↑, shear modulus G, bulk modulus B, Young’s modulus E, Debye temperature ΘD, melting temperature Tmelt, static dielectric constant ε1(0), maximum imaginary part of the dielectric constant ε2(ω)max, maximum reflective index R(ω)max, and static refractive index n(0) decrease for Y2CrSi, Y2CrGe, and Y2CrSn successively. Increases in both Poisson’s ratio υ and Pugh’s ratio B/G indicate the ductile character increases for Y2CrSi, Y2CrGe, and Y2CrSn successively. The highest global maximum value in the energy loss function L(ω) spectra of these three alloys indicates that Y2CrSn is the most suitable material to make a far-ultraviolet photodetector.