Predicting and controlling permanent magnet functionalities from theory and computation*

The very first criterion for permanent magnetic material prediction is crystal structure which allows magnetic moments to align along the anisotropic crystal axis. Hexagonal and tetragonal structures do fall within this category. The non-equivalent crystal sites in a complex structure play a key role in determining the magnetic moments, uniaxial magnetic anisotropy, and chemical stability. Employing advanced density functional theory (DFT), which includes electron correlation and spin orbit coupling, we first analyze theoretically predicted intrinsic permanent magnetic properties (magneto-crystalline anisotropy, magnetic moment, and magnetic order-disorder transition temperature) of known model permanent magnetic materials such as Nd₂Fe₁₄B, NdFe₁₂N, SmCo₅, and Sm₂Co₁₇. Next, we present how our electronic structure calculations with site substitution mechanism allow us to reduce critical rare earths and transition elements without affecting intrinsic permanent magnetic properties.