Systematic DFT Study of Composition-Tunable Antiferromagnetism and Elastic Anisotropy in Cubic X ₂ NdIn (X=Cu, Ag, Au) Heusler Alloys

We performed first-principles calculations in the framework of density functional theory (DFT), based on the full potential linearized augmented plane wave (FP-LAPW) for a series of full-Heusler compounds based on neodymium rare-earth X 2 NdIn ([Formula: see text]Cu, Ag, Au), to investigate their structural, mechanical, magnetic and electronic properties. All compounds crystallize in the cubic L 2 1 structure with lattice parameters consistent with experimental values. Crucially, elastic constant calculations reveal significant elastic anisotropy despite cubic symmetry, demonstrated by nonzero universal anisotropy indices (A[Formula: see text]0) while mechanical stability is confirmed via Born criteria. Magnetic ground-state scans identify distinct antiferromagnetic configurations for each [Formula: see text], implying tunable antiferromagnetic order as a function of chemical composition. Electronic structure analyses confirm metallic behavior with systematically reduced Nd[Formula: see text] moments due to correlated electron effects. The combined presence of elastic anisotropy in a cubic structure and composition-dependent antiferromagnetism highlights the potential of these Heusler alloys as promising candidates for cryogenic magneto-mechanical sensors.