First-principles study of structural stability and magnetic properties in Fe–Pd–In alloys

In this study, we investigate the structural stability and magnetic properties of Fe − Pd-based ternary alloys. First-principles calculations are employed to analyze the stability of the Z 3-Fe 2 Pd 6 structure with In substitution and to evaluate the magnetic anisotropy energy (MAE) of Z 3-Fe 2 Pd 5 In 1 . This structural modification is attributed to the unique inter-element miscibility of In with Pd and its immiscibility with Fe, which stabilizes the Z 3 phase. Furthermore, the enhanced magnetic coercivity observed in Z 3-Fe 2 Pd 5 In 1 compared to the L 1 2 -FePd 3 phase highlights the potential of controlling atomic ordering and inter-element interactions to design novel functional materials. Our findings also demonstrate that the magnetic anisotropy energy is highly sensitive to the lattice parameters. While the ideal structure exhibits in-plane anisotropy, a small compressive strain on the a -axis can induce a switch to uniaxial anisotropy, providing a plausible explanation for the experimentally observed coercivity. These insights provide a deeper understanding of the relationship between atomic-scale structural changes and macroscopic magnetic properties, offering valuable guidelines for the development of advanced magnetic materials. • First-principles calculations reveal Z 3 phase stability in Fe-Pd-In alloys. • Inter-element miscibility is key to stabilizing the Z 3-Fe 2 Pd 5 X structure. • Magnetic anisotropy is highly sensitive to lattice strain in Z 3-Fe-Pd-In. • Strain can switch magnetic anisotropy from in-plane to uniaxial. • Theory explains coercivity in both In (high) and Pb (low) doped systems.