Electronic Structure of La–Co Substituted Strontium Hexaferrite (Sr1 - xLaxFe12 - xCoxO19) Permanent Magnet

We report electronic structures of M-type SrFe
₁₂
O
₁₉
and La
³⁺
- Co
²⁺
pair substituted Sr
_1-x
La
_x
Fe
_1-x
Co
_x
O
₁₉
ferrites (x = 0.1 - 0.5). First-principles calculations were performed on the ferrites to calculate electronic structures. The substitution of La
³⁺
- Co
²⁺
in the 2d and 2a sites decreased the lattice constants and total magnetic moment per unit cell. The moments at 2b, 12k, 4 f1, and 4 f2 sites are not affected by the substitution. Nonsubstituted SrFe
₁₂
O
₁₉
is a semiconductor, but becomes half-metallic when La
³⁺
and Co
²⁺
are substituted in the 2d and 2a sites, respectively.