Magnetic and electronic properties of strontium hexaferrite SrFe12O19 from first-principles calculations

Abstract

The magnetic and electronic structure of strontium hexaferrite SrFe12O19 has been investigated using density functional theory within the local spin density approximation. The calculations show that in this ferrite all the Fe3+ 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 Fe3+ ions at the 4f sites having their spin polarization anti-parallel to the rest of the Fe3+ ions, in agreement with Gorter's prediction. The ferrite SrFe12O19 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.