2007/04/29 by A. Biltmo, P. Henelius · 4 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic properties of thin films #Theoretical and Computational Physics #cond-mat.dis-nn #cond-mat.stat-mech
paper · pdf · doi:10.1103/physrevb.76.054423
published as Phys. Rev. B 76, 054423 (2007) · 5 pages, 4 figures
arxiv created 2007/04/29 · openalex publication_date 2007/08/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We study the effective long-range Ising dipole model with a local exchange interaction appropriate for the dilute magnetic compound LiHoxY_1\ensuremath-xF4. Our calculations yield a value of 0.12\phantom\rule0.3em0exK for the nearest-neighbor exchange interaction. Using a Monte Carlo method, we calculate the phase boundary Tc(x) between the ferromagnetic and paramagnetic phases. We demonstrate that the experimentally observed linear decrease in Tc with dilution is not the simple mean-field result, but a combination of the effects of fluctuations and the exchange interaction. Furthermore, we find a critical dilution xc=0.21(2), below which there is no ordering. In agreement with recent Monte Carlo simulations on a similar model, we find no evidence of the experimentally observed freezing of the glassy state in our calculation. We apply the theory of Stephen and Aharony to LiHoxY_1\ensuremath-xF4 and find that the theory does predict a finite-temperature freezing of the spin glass. Reasons for the discrepancies are discussed.