Magnon spectrum and related finite-temperature magnetic properties: A first-principle approach

It is shown that the magnon spectrum of magnetically ordered crystals can be calculated using a frozen magnon scheme and spin density functional theory in the local approximation. Ab initio calculated magnon spectra for Fe and Ni are presented. Kohn anomalies are predicted for the magnon spectrum of Fe. Considering the magnons as true low-lying thermal excitations and using mean-field semi-classical statistics at elevated temperatures, the finite-temperature magnetization and Curie temperature T C are calculated, which compare well with experiment for Fe, Co, and Ni.