Metadynamics Study Of The Temperature Dependence Of Magnetic Anisotropy And Spin-Reorientation Transitions In Ultrathin Films

We employ metadynamics simulations to calculate the free-energy landscape of thin ferromagnetic films and perform a systematic study of the temperature dependence of magnetic anisotropy and of the spin-reorientation transitions. By using a simple spin model we recover the well-known power-law behavior of the magnetic anisotropy energy against magnetization and present a rather detailed analysis of the spin-reorientation transitions in ultrathin films. Based on tensorial exchange interactions and anisotropy parameters derived from first-principles calculations, we perform simulations for Fe double layers deposited on Au(001) and W(110). In the case of Fe2W(110) our simulations display an out-of-plane to in-plane spin-reorientation transition in agreement with experiments.