Eur. Phys. J. B 42, 549-553 (2004)
https://doi.org/10.1140/epjb/e2005-00013-y

Anisotropic field dependence of the magnetic transition in Cu₂Te₂O₅Br₂

¹ Laboratorium für Festkörperphysik, ETH Hönggerberg, 8093 Zürich, Switzerland
² Centre d'Elaboration de Matériaux et d'Études Structurales, CEMES/CNRS, 31062 Toulouse, France

Corresponding author: ^a sologubenko@solid.phys.ethz.ch

Received: 28 June 2004
Revised: 24 September 2004
Published online: 18 January 2005

Abstract

In this paper, we present the results of measurements of the thermal conductivity of Cu₂Te₂O₅Br₂, a compound where tetrahedra of Cu²⁺ ions carrying S=1/2 spins form chains along the c-axis of the tetragonal crystal structure. The thermal conductivity κ was measured along both the c- and the a-direction as a function of temperature between 3 and 300 K and in external magnetic fields H up to 69 kOe, oriented both parallel and perpendicular to the c-axis. Distinct features of were observed in the vicinity of  K in zero magnetic field. These features are unaltered in external fields which are parallel to the c-axis, but are more pronounced when a field is applied perpendicularly to the c-axis. The transition temperature increases upon enhancing the external field, but only if the field is oriented along the a-axis.