1. Lattice dynamics effects on the magnetocrystalline anisotropy energy: application to MnBi
- Author
-
Andrea Urru and Andrea Dal Corso
- Subjects
Physics ,Condensed Matter - Materials Science ,Condensed matter physics ,Phonon ,Plane (geometry) ,Transition temperature ,Binary compound ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Computational Physics (physics.comp-ph) ,Magnetocrystalline anisotropy ,Settore FIS/03 - Fisica della Materia ,chemistry.chemical_compound ,Magnetization ,Condensed Matter::Materials Science ,chemistry ,Ferromagnetism ,Physics - Materials Science ,Perturbation theory ,Physics - Computational Physics - Abstract
Using a first-principles fully relativistic scheme based on ultrasoft pseudopotentials and density functional perturbation theory, we study the magnetocrystalline anisotropy free energy of the ferromagnetic binary compound MnBi. We find that differences in the phonon dispersions due to the different orientations of the magnetization (in-plane and perpendicular to the plane) give a difference between the vibrational free energies of the high-temperature and low-temperature phases. This vibrational contribution to the magnetocrystalline anisotropy energy (MAE) constant, $K_u$, is non-negligible. When the energy contribution to the MAE is calculated by the PBEsol exchange and correlation functional, the addition of the phonon contribution allows to get a $T = 0$ K $K_u$ and a spin-reorientation transition temperature in reasonable agreement with experiments., Comment: 6 pages, 4 figures, 2 tables
- Published
- 2020
- Full Text
- View/download PDF