2003/11/06 by Òscar Iglesias, Oscar Iglesias, Amilcar Labarta +1
Engineering · Physics and Astronomy · #Characterization and Applications of Magnetic Nanoparticles #Magnetic properties of thin films #Theoretical and Computational Physics #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.70.144401
published as Phys. Rev. B 70, 144401 (2004) · 11 pages, 10 figures
arxiv created 2003/11/06 · openalex publication_date 2004/10/11 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
The magnetic relaxation and hysteresis of a system of single domain particles with dipolar interactions are studied by Monte Carlo simulations. We model the system by a chain of Heisenberg classical spins with randomly oriented easy-axis and log-normal distribution of anisotropy constants interacting through dipole-dipole interactions. Extending the so-called T\phantom\rule0.2em0exln(t∕\ensuremathτ0) method to interacting systems, we show how to relate the simulated relaxation curves to the effective energy barrier distributions responsible for the long-time relaxation. We find that the relaxation law changes from quasilogarithmic to power-law when increasing the interaction strength. This fact is shown to be due to the appearance of an increasing number of small energy barriers caused by the reduction of the anisotropy energy barriers as the local dipolar fields increase.