Electronic structure and magnetic anisotropies of antiferromagnetic transition-metal difluorides

We compare calculations based on density functional theory (DFT) with available experimental data and analyze the origin of magnetic anisotropies in MnF₂, FeF₂, CoF₂, and NiF₂. We confirm that the magnetic anisotropy of MnF₂ stems almost completely from the dipolar interaction, while magnetocrystalline anisotropy energy (originating in spin-orbit interaction) plays a dominant role in the other three compounds, and discuss how it depends on the details of band structure. The latter is critically compared to available optical measurements. The case of CoF₂, where magnetocrystalline anisotropy energy strongly depends on U (the Hubbard parameter in DFT+U), is put into contrast with FeF₂ where theoretical predictions of magnetic anisotropies are nearly quantitative.