The role of vortices in the three-dimensional random-field xy model
Physics Department, Lehman College, City University of New York - 250 Bedford Park Boulevard West, Bronx, NY 10468-1589, USA
Received: 28 July 2013
Accepted: 20 September 2013
We study vortex states in a 3d random-field xy model of up to one billion lattice spins at T = 0. Starting with random spin orientations, the sample freezes into the vortex-glass state with a stretched-exponential decay of spin correlations, having short correlation length and a low susceptibility, compared to vortex-free states. In a field opposite to the initial magnetization, peculiar topological objects —walls of spins still opposite to the field— emerge along the hysteresis curve. On increasing the field strength, the walls develop cracks bounded by vortex loops. The loops then grow in size and eat the walls away. Applications to magnets and superconductors are discussed.
PACS: 74.25.Uv – Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses) / 75.10.Nr – Spin-glass and other random models / 64.60.De – Statistical mechanics of model systems (Ising model, Potts model, field-theory models, Monte Carlo techniques, etc.)
© EPLA, 2013