Comment on `Ising Pyrochlore Magnets: Low Temperature Properties, ``Ice Rules,'' and Beyond' by R. Siddharthan et al., Phys. Rev. Lett. 83, 1854 (1999)

TL;DR

This paper challenges prior claims of partial order in Ho$_2$Ti$_2$O$_7$, arguing it exhibits spin ice behavior and that its specific heat data can be explained by a dipolar spin ice model including nuclear spin contributions.

Contribution

It refutes the previous claim of a transition to partial order and supports the spin ice behavior in Ho$_2$Ti$_2$O$_7$, providing a revised interpretation of experimental data.

Findings

Ho$_2$Ti$_2$O$_7$ does not show a transition to partial order

Experimental specific heat data can be explained by dipolar spin ice model

Nuclear Ho spins contribute significantly to the specific heat

Abstract

In this Comment we argue that Ho$_2$Ti$_2$O$_7$ does not exhibit a transition to a partially ordered state unlike what is argued in PRL 83, 1854 (1999), that it exhibits spin ice behavior, and that the experimental specific heat data by Siddharthan et al. can be accounted for in terms of a "dipolar spin ice" model by including an expected contibution from the nuclear Ho spins to the appropriate long-range treatment of the dipole-dipole interactions.