Metastability of Ising spin chains with nearest-neighbour and next-nearest-neighbour interactions in random fields

摘要

One-dimensional Ising systems in random fields(RFs) are studied taking into account the nearest-neighbour and next-nearest-neighbour interactions. We investigate two distributions of RFs: binary and Gaussian distributions. We consider four cases of the exchange couplings: ferro-ferromagnetic(F-F), ferro-antiferromagnetic(F-AF), antiferro- ferromagnetic(AF-F) and antiferro-antiferromagnetic(AF-AF). The energy minima of chains of no more than 30 spins with periodic boundary conditions are analysed exactly. We found that the average number of energy minima grows exponentially with the number of spins in both cases of RFs.