Heat transport of quasi-one-dimensional Ising-like antiferromagnet BaCo_2V_2O_8 in the longitudinal and transverse fields

TL;DR

This study investigates the thermal conductivity of BaCo_2V_2O_8, revealing magnetic field-induced transitions and scattering mechanisms in a quasi-one-dimensional Ising-like antiferromagnet at very low temperatures.

Contribution

It provides experimental insights into magnetic field-induced transitions and thermal transport behavior in BaCo_2V_2O_8, highlighting phenomena not predicted by existing theories.

Findings

Thermal conductivity drops at ~4 T indicating a transition from Néel order to incommensurate state.

A dip at ~3 T suggests an unknown magnetic transition, likely a spin-flop transition.

Deep valley in ppa(H) in transverse field indicates a magnetic transition not explained by current theories.

Abstract

The very-low-temperature thermal conductivity (\kappa) is studied for BaCo_2V_2O_8, a quasi-one-dimensional Ising-like antiferromagnet exhibiting an unusual magnetic-field-induced order-to-disorder transition. The nearly isotropic transport in the longitudinal field indicates that the magnetic excitations scatter phonons rather than conduct heat. The field dependence of \kappa shows a sudden drop at \sim 4 T, where the system unndergoes the transition from the N\'eel order to the incommensurate state. Another dip at lower field of \sim 3 T indicates an unknown magnetic transition, which is likely due to the spin-flop transition. Moreover, the \kappa(H) in the transverse field shows a very deep valley-like feature, which moves slightly to higher field and becomes sharper upon lowering the temperature. This indicates a magnetic transition induced by the transverse field, which however is not predicted by the present theories for this low-dimensional spin system.