Heat transport of the quasi-one-dimensional alternating spin chain material (CH_{3})_{2}NH_{2}CuCl_{3}

TL;DR

This study investigates how low-temperature heat transport in a quasi-one-dimensional spin chain compound is affected by magnetic excitations and external magnetic fields, revealing complex interactions and state transitions.

Contribution

It provides new insights into the role of spin excitations as phonon scatterers and their influence on thermal conductivity across various magnetic states.

Findings

Magnetic excitations mainly scatter phonons from 0.3 to 30 K.

Thermal conductivity changes drastically at magnetic field-induced transitions.

High magnetic fields enhance phonon conductivity by reducing spin fluctuations.

Abstract

We report a study of the low-temperature heat transport in the quasi-one-dimensional S = 1/2 alternating antiferromagnetic-ferromagnetic chain compound (CH_{3})_{2}NH_{2}CuCl_{3}. Both the temperature and magnetic-field dependencies of thermal conductivity are very complicated, pointing to the important role of spin excitations. It is found that magnetic excitations act mainly as the phonon scatterers in a broad temperature region from 0.3 to 30 K. In magnetic fields, the thermal conductivity show drastic changes, particularly at the field-induced transitions from the low-field N\'{e}el state to the spin-gapped state, the field-induced magnetic ordered state, and the spin polarized state. In high fields, the phonon conductivity is significantly enhanced because of the weakening of spin fluctuations.