The random-field specific heat critical behavior at high magnetic concentration: Fe(0.93)Zn(0.07)F2

TL;DR

This study investigates the critical behavior of specific heat in a high magnetic concentration random-field Ising system, revealing a symmetric logarithmic divergence and establishing the equivalence of measurement techniques.

Contribution

It provides the first detailed experimental analysis of the specific heat critical behavior in Fe(0.93)Zn(0.07)F2, a high concentration random-field Ising system, and compares it with theoretical predictions.

Findings

Critical peak shows symmetric, logarithmic divergence.

High concentration sample behaves as an equilibrium system.

Random-field specific heat scaling function is determined.

Abstract

The specific heat critical behavior is measured and analyzed for a single crystal of the random-field Ising system Fe(0.93)Zn(0.07)F2 using pulsed heat and optical birefringence techniques. This high magnetic concentration sample does not exhibit the severe scattering hysteresis at low temperature seen in lower concentration samples and its behavior is therefore that of an equilibrium random-field Ising model system. The equivalence of the behavior observed with pulsed heat techniques and optical birefringence is established. The critical peak appears to be a symmetric, logarithmic divergence, in disagreement with random-field model computer simulations. The random-field specific heat scaling function is determined.