Phase Diagram of the Two-Dimensional Ising Model with Random Competing Interactions

Abstract

An Ising model with ferromagnetic nearest-neighbor interactions $J_1$ ($J_1>0$) and random next-nearest-neighbor interactions [$+J_2$ with probability $p$ and $-J_2$ with probability $(1-p)$; $J_2>0$] is studied within the framework of an effective-field theory based on the differential-operator technique. The order parameters are calculated, considering finite clusters with $n=1,2,\mathrm{and}4$ spins, using the standard approximation of neglecting correlations. A phase diagram is obtained in the plane temperature versus $p$, for the particular case $J_1=J_2$, showing both superantiferromagnetic (low $p$) and ferromagnetic (higher values of $p$) orderings at low temperatures.

References in corpus (2)

• Phase diagram of the Ising square lattice with competing interactions
• Quenched bond randomness in marginal and non-marginal Ising spin models in 2D