First-principles investigation on structural, electronic, magnetic, mechanical and thermodynamic properties of half-metallic Zn-based all-d-metal equiatomic quaternary Heusler alloys

Abstract

This study employs first-principles calculations based on density functional theory (DFT) to investigate the structural, electronic, magnetic, mechanical, and thermodynamic properties of Zn-based all-d-metal equiatomic quaternary Heusler alloys (EQHAs) XX'YZn (X = Fe, Ni, Co; X' = V, Cr; Y = Nb, Ti, Zr, Hf). The investigation encompasses three distinct structural types of all-d EQHAs, with the energy calculations revealing the Type-I configuration as the most stable. The electronic structure of the all-d EQHAs demonstrate 100% spin polarization. Specifically, NiVTiZn and NiVZrZn exhibit characteristics of half-metallic ferromagnets, while FeVNbZn, CoCrTiZn, CoCrZrZn, and CoCrHfZn manifest traits of half-metallic ferrimagnets. Notably, we have conducted computations concerning the magnetic properties of these six alloys, revealing that their principal magnetic moments stem from V and Cr atoms. This study analyzes the influence of lattice constant variations on the magnetic properties of the alloys and the width of the spin down energy gap. Results demonstrate that within the ranges of lattice constants from 5.6 Å to 6.4 Å for FeVNbZn, 5.5–6.6 Å for NiVTiZn, 5.8–6.8 Å for NiVZrZn, 5.8–6.7 Å for CoCrTiZn, 5.9–6.8 Å for CoCrZrZn and 6.0–6.9 Å for CoCrHfZn, these alloys maintain their stable half-metallic attributes. Furthermore, the investigated alloys demonstrate mechanical stability, exhibiting ductility and anisotropic characteristics. These investigations underscore the potential application prospects of half-metallic all-d EQHAs in spintronic devices.