Single ion scattering contributions to the thermal conductivity of LiHoF_4 and LiY_{96%}Ho_{4%}F_4

TL;DR

This study measures the thermal conductivity of LiHoF and LiY_{96%}Ho_{4%}F_4 single crystals below 2.3 K, revealing dominant single-ion scattering in the former and additional effects possibly from collective excitations in the latter.

Contribution

It provides the first detailed comparison of thermal conductivity with a single ion scattering model for these materials, highlighting different scattering mechanisms.

Findings

LiYHoF's thermal conductivity is dominated by single-ion scattering.

LiHoF shows additional contributions, likely from collective spin excitations.

No comprehensive model fully explains the ferromagnetic thermal conductivity.

Abstract

We have performed extensive zero-field thermal conductivity measurements on single crystal samples of \LiHoF and \LiYHoF below $2.3 K$. By comparing these data to a single ion scattering model, we have shown that the thermal conductivity of \LiYHoF is dominated by simple single-ion scattering while that of \LiHoF shows additional contributions, possibly associated with collective spin excitations. No entirely satisfactory model, however, is available to explain the thermal conductivity of the ferromagnet.