Eur. Phys. J. B 30, 83-92 (2002)
https://doi.org/10.1140/epjb/e2002-00361-0

Ising magnets with mobile defects

¹ Institut für Theoretische Physik, Technische Hochschule, 52056 Aachen, Germany
² Department of Physics, Texas A&M University, College Station, Texas, 77843-4242, USA
³ 2. Physikalisches Institut, Technische Hochschule, 52056 Aachen, Germany

Corresponding author: ^a selke@physik.rwth-aachen.de

Received: 22 August 2002
Revised: 4 October 2002
Published online: 19 November 2002

Abstract

Motivated by recent experiments on cuprates with low-dimensional magnetic interactions, a new class of two-dimensional Ising models with short-range interactions and mobile defects is introduced and studied. The non-magnetic defects form lines, which, as temperature increases, first meander and then become unstable. Using Monte Carlo simulations and analytical low- and high-temperature considerations, the instability of the defect stripes is monitored for various microscopic and thermodynamic quantities in detail for a minimal model, assuming some of the couplings to be indefinitely strong. The robustness of the findings against weakening the interactions is discussed as well.