Thermodynamic Properties of the Dipolar Spin Ice Model

TL;DR

This paper provides a comprehensive theoretical analysis of the thermodynamic properties of the dipolar spin ice model, demonstrating its ability to replicate experimental behaviors of pyrochlore materials and exploring field-induced ordering phenomena.

Contribution

It offers a detailed theoretical overview including the use of Ewald summation, mean field theory, and Monte Carlo simulations to understand spin ice behavior and field effects.

Findings

Reproduces spin ice behavior with long-range dipolar interactions

Identifies low-temperature ordered states via simulations and theory

Predicts various long-range orders depending on magnetic field direction

Abstract

We present a detailed theoretical overview of the thermodynamic properties of the dipolar spin ice model, which has been shown to be an excellent quantitative descriptor of the Ising pyrochlore materials Dy_2Ti_2O_7 and Ho_2Ti_2O_7. We show that the dipolar spin ice model can reproduce an effective quasi macroscopically degenerate ground state and spin-ice behavior of these materials when the long-range nature of dipole-dipole interaction is handled carefully using Ewald summation techniques. This degeneracy is, however, ultimately lifted at low temperature. The long-range ordered state is identified via mean field theory and Monte Carlo simulation techniques. Finally, we investigate the behavior of the dipolar spin ice model in an applied magnetic field, and compare our predictions with experimental results. We find that a number of different long-range ordered states are favored by the model depending on field direction.