HR: 08:15h
AN: V21A-02    [PDF]
TI: Towards First Principles Spin Dynamics Calculations of the Magnetic Structure of Materials
AU: * Stocks, M
EM: gms@ornl.gov
AF: Oak Ridge National Laboratory, P.O. Box 2008-6114, Oak Ridge, TN 37831-6114 United States
AU: Ujfalussy, B
EM: v6f@ornl.gov
AF: Oak Ridge National Laboratory, P.O. Box 2008-6114, Oak Ridge, TN 37831-6114 United States
AU: Eisenbach, M
EM: me4@ornl.gov
AF: Oak Ridge National Laboratory, P.O. Box 2008-6114, Oak Ridge, TN 37831-6114 United States
AB: At the microscopic level, the same electrons that give rise to metallic cohesion are also responsible for moment formation and the other intrinsic (exchange interactions, anisotropy energies.) and extrinsic (coercivity, remanance.) properties of magnetic materials. Despite this complexity it is possible, in many systems, to isolate fast and slow degrees of freedom that are respectively responsible for moment formation and moment dynamics. In first principles spin dynamics (FP-SD) fast moment formation is described by electronic structure methods, whilst the slow moment reorientation is described by a Landau-Lifshitz like equation. In this presentation I will outline the theory of FP-SD based on a the constrained local moment model for calculating the magnetic moments, energy and forcing fields required at each time step in the evolution of the orientational states given by the Landau-Lifshitz equation. In addition I will outline the application of FP-SD to study to the study of complex non-collinear magnetic structures of inhomogeneous systems based of FP methods capable of treating large numbers of atoms. Studies of the magnetic structure of disordered gamma-phase FeMn alloys, Co/FeMn interfaces, and quantum corrals will be used to illustrate the theory. Work sponsored by BES-DMSE US-DOE, under Contract DE-AC05-00OR227725. Computational work performed at CCS-ORNL and NERSC.
DE: 8499 General or miscellaneous
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting