Phase transitions in systems of magnetic dipoles on a square lattice with quenched disorder

2008/09/14 by Juan J. Alonso, J. J. Alonso, Alonso, J. J.
Physics and Astronomy · #Magnetic properties of thin films #Theoretical and Computational Physics #cond-mat.stat-mech

paper · pdf · doi:10.48550/arxiv.0809.2381

4 pages, 5 EPS figures

arxiv created 2008/09/14 · arxiv updated 2009/12/01

Abstract

We study by Monte Carlo simulations the effect of quenched orientational disorder in systems of interacting classical dipoles on a square lattice. Each dipole can lie along any of two perpendicular axes that form an angle psi with the principal axes of the lattice. We choose psi at random and without bias from the interval [-Delta, Delta] for each site of the lattice. For 0<Delta <~ pi/4 we find a thermally driven second order transition between a paramagnetic and a dipolar antiferromagnetic order phase and critical exponents that change continously with Delta. Near the case of maximum disorder Delta ~ π/4 we still find a second order transition at a finite temperature T_c but our results point to weak instead of \it strong long-ranged dipolar order for temperatures below T_c.

Related

• On the phase diagram of a three-dimensional dipolar model
• Phase Transition of 3D Heisenberg Magnet in Presence of Random-Bond Disorder
• Effects of Quenched Randomness on Classical and Quantum Phase Transitions
• Circular phase of a two dimensional ferromagnet with dipolar interactions
• Quantitative disorder effects in low-dimensional spin systems