Specific Heat of Kagome Ice in the Pyrochlore Oxide Dy2Ti2O7

TL;DR

This study investigates the specific heat of kagome ice in Dy2Ti2O7, revealing its residual entropy, phase behavior under magnetic fields, and confirming theoretical predictions about its degenerate state.

Contribution

It provides experimental specific heat data for kagome ice in Dy2Ti2O7, confirming theoretical entropy estimates and phase transition behavior under magnetic fields.

Findings

Residual entropy of kagome ice is 0.65 J/K mol Dy.

Kagome ice transitions from a 'gas' to a 'liquid' phase near 1 T.

The experimental entropy agrees with theoretical predictions.

Abstract

A novel macroscopically degenerate state called kagome ice, which was recently found in a spin ice compound Dy2Ti2O7 in a magnetic field applied along the [111] direction of the cubic unit cell, is studied by specific heat measurements. The residual entropy of the kagome ice is estimated to be 0.65 J/K mol Dy, which is nearly 40 % of that for the tetrahedral spin ice obtained in a zero field (1.68 J/K mol Dy) and is in good agreement with a theoretical prediction. It is also reported that the kagom ice state, which is stabilized at a range of magnetic field of 0.3 ~ 0.6 T, is a 'gas' phase and condenses into a 'liquid' phase with nearly zero entropy at a critical field of 1 T.