Low-temperature heat transport of the zigzag spin-chain compound SrEr₂O₄

Low-temperature thermal conductivity (\kappa), as well as the magnetic properties and specific heat, are studied for the frustrated zigzag spin-chain material SrEr_2O_4 by using single-crystal samples. The specific heat data indicate the long-range antiferromagnetic transition at \sim 0.73 K and the existence of strong magnetic fluctuations. The magnetizations at very low temperatures for magnetic field along the c axis (spin chain direction) or the a axis reveal the field-induced magnetic transitions. The \kappa shows a strong dependence on magnetic field, applied along the c axis or the a axis, which is closely related to the magnetic transitions. Furthermore, high magnetic field induces a strong increase of \kappa . These results indicate that thermal conductivity along either the c axis or the a axis are mainly contributed by phonons, while magnetic excitations play a role of scattering phonons.