Stretched-exponential relaxation in two-dimensional easy-plane ferromagnets
Physikalisches Institut, Universität Bayreuth - D-95440
2 Theoretical Division and Center for Nonlinear Studies Los Alamos National Laboratory - Los Alamos, NM 87545, USA
Accepted: 14 November 2002
A classical ferromagnet is described in a continuum approximation and at the microscopic level by the Landau-Lifshitz equation. In two spatial dimensions, vortices are the topological solutions of the model in the presence of easy-plane anisotropy. We argue that a system of vortices has an energy landscape whose gross features can be well described. We investigate numerically the effect of the complex energy landscape on the relaxation dynamics, namely a characteristic stretched-exponential decrease in the energy and the number of vortices present in the system as the system relaxes toward the ground state.
PACS: 75.10.Hk – Classical spin models / 75.70.Kw – Domain structure (including magnetic bubbles) / 87.15.-v – Biomolecules: structure and physical properties
© EDP Sciences, 2003