Diluted Random Fields in Mixed Cyanide Crystals

TL;DR

This paper presents a simple model for mixed cyanide crystals using a dilute random field Ising model, accurately reproducing phase diagram features and critical thresholds, and explaining the nature of phase transitions.

Contribution

It introduces a novel application of a dilute random field Ising model to describe phase transitions in mixed cyanide crystals, matching experimental data.

Findings

Critical thresholds x_c where first order transitions vanish

Transitions remain first order down to x_c except for bromine

Model results align with experimental phase diagrams

Abstract

A percolation argument and a dilute compressible random field Ising model are used to present a simple model for mixed cyanide crystals. The model reproduces quantitatively several features of the phase diagrams altough some crude approximations are made. In particular critical thresholds x_c at which ferroelastic first order transitions disappear, are calculated. Moreover, transitions are found to remain first order down to x_c for all mixtures except for bromine, for which the transition becomes continuous. All the results are in full agreement with experimental data.