Crossover from random-exchange to random-field critical behavior in Ising models

Crossover from pure Ising to random-exchange dominated behavior of the two-dimensional antiferromagnet Rb2Co1-xMgxF4

Critical behavior of the random-field Ising model.

We study the critical properties of the random field Ising model in general dimension d using hightemperature expansions for the susceptibility, χ=∑j[〈σiσj⟩T-〈σi⟩T〈σj⟩T]h and the structure factor, G=∑j[〈σiσj⟩T]h, where 〈⟩T indicates a canonical average at temperature T for an arbitrary configuration of random fields and [ ]h indicates an average over random fields. We treated two distributions ...

Random–Field Ising Models of Hysteresis

This is a review article of our work on hysteresis, avalanches, and criticality. We provide an extensive introduction to scaling and renormalization–group ideas, and discuss analytical and numerical results for size distributions, correlation functions, magnetization, avalanche durations and average avalanche shapes, and power spectra. We focus here on applications to magnetic Barkhausen noise,...

Nature of crossover from classical to Ising-like critical behavior

We present an accurate numerical determination of the crossover from classical to Ising-like critical behavior upon approach of the critical point in three-dimensional systems. The possibility of varying the Ginzburg number in our simulations allows us to cover the entire crossover region. We employ these results to scrutinize several semiphenomenological crossover scaling functions that are wi...

Random Field Ising Model

This paper gives an introduction to the Random Field Ising Model (RFIM). Since its rst discussion in the paper by Imry and Ma 1] there has been great interest in this model, since Ising or Ising-like systems in random elds are a good representation of a large number of impure materials. These show features that can not be understood by studying ideal systems (i.e. Ising model). There are a lot ...