Magnetic and electronic properties of strontium hexaferrite SrFe₁₂O₁₉from first-principles calculations

The magnetic and electronic structure of strontium hexaferrite SrFe 12 O 19 has been investigated using density functional theory within the local spin density approximation. The calculations show that in this ferrite all the Fe 3+ ions are fully spin polarized with S = 5/2. The electronic structure of this ferrite is strongly influenced by the exchange interactions between the iron ions. The most stable form of the ferrite is a ferrimagnet with the Fe 3+ ions at the 4f sites having their spin polarization anti-parallel to the rest of the Fe 3+ ions, in agreement with Gorter's prediction. The ferrite SrFe 12 O 19 is calculated to be a semiconductor with both the top of the valence band and the bottom of the conduction band being dominated by Fe 3d states. A strong anisotropy was found for the conductive charge carriers. The calculated results are in good agreement with the available experimental data.