Site specific physics in RT$_{5}$ (R $=$ rare earths and T $=$ transition metals) materials*

Most of RT$_{5}$ compounds form in hexagonal CaCu$_{5}$-type structure with three non-equivalent sites: R (1a), T (2c), and T (3g). R atoms sit in the middle of the T (2c) hexagonal layers. Advanced density functional theory calculations including on-site electron correlation and spin orbit coupling show crystal field split localized R 4f states, which are responsible for the large part of the magnetic anisotropy exhibited by these systems. In addition, the hexagonal T (2c) layers help enhancing the magnetic anisotropy. Partially quenched R 4f orbital moment is the origin of magnetic anisotropy which also helps enhancing magnetic moment. The interchange of T sites by other transition metals and the partial substitution of R atoms by transition metals could optimize needed magnetic moment and magnetic anisotropy by forming a complex geometry structure favoring permanent magnetic properties.