Berlin 2015 – wissenschaftliches Programm
TT 40.3: Vortrag
Dienstag, 17. März 2015, 10:00–10:15, H 0112
Navigation on the energy surface of the noncollinear Alexander-Anderson model using a magnetic force theorem — •Pavel Bessarab1,2, Valery Uzdin2,3, and Hannes Jónsson4,5 — 1Royal Institute of Technology KTH, Stockholm, Sweden — 2St. Petersburg State University, St. Petersburg, Russia — 3St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg, Russia — 4University of Iceland, Reykjavik, Iceland — 5Aalto University, Espoo, Finland
Magnetic force theorem is derived within the multiple impurity, noncollinear Alexander-Anderson (NCAA) model - an important tool for efficient calculation of the total energy gradient with respect to orientation of magnetic moments, the magnetic 'forces'. Efficient evaluation of magnetic forces is of great importance for the large scale simulation of spin dynamics, minimization of the energy to identify stable and metastable magnetic states, or, in general, navigation on the energy surface of a magnetic system. NCAA model and magnetic force theorem are applied to calculate minimum energy paths between stable magnetic states of the monolayer Fe clusters on a W(110) surface, revealing complex mechanism of the magnetization reversal. Moreover, a noncollinear magnetic state is identified in a 7 x 7 atomic row Fe island where the magnetic moments are arranged in an antivortex configuration with the central ones pointing out of the (110) plane. The minimum energy path between this antivortex state and the collinear ground state is also calculated and the thermal stability of the antivortex state estimated.