Finite Temperature Transitions in Large Magnetic Field in Dipolar Spin Ice

TL;DR

This paper uses Monte Carlo simulations to explore how phase transitions in dipolar spin ice persist under large magnetic fields, revealing mechanisms and specific conditions that lead to long-range order.

Contribution

It identifies the decoupling mechanism of spins in high magnetic fields and details the transition to q=X order along the [110] direction, advancing understanding of spin ice behavior.

Findings

Spin decoupling occurs on one sublattice under high fields.

Transition to q=X order along [110] direction.

Relevance to specific heat features in Dy2Ti2O7.

Abstract

We use Monte Carlo simulations to identify the mechanism that allows for phase transitions in dipolar spin ice to occur and survive for applied magnetic field, H, much larger in strength than that of the spin-spin interactions. In the most generic and highest symmetry case, the spins on one out of four sublattices of the pyrochlore decouple from the total local exchange+dipolar+applied field. In the special case where H is aligned perfectly along the [110] crystallographic direction, spin chains perpendicular to H show a transition to q=X long range order, which proceeds via a one to three dimensional crossover. We propose that these transitions are relevant to the origin of specific heat features observed in powder samples of the Dy2Ti2O7 spin ice material for H above 1 Tesla.