Neutron Diffraction Study of Distorted-Triangular-Lattice Ising-like Antiferromagnet TlCoCl₃

Abstract

A powder and single-crystal neutron diffraction study was performed on the structural and magnetic phase transitions of the distorted-triangular-lattice Ising-like antiferromagnet TlCoCl₃. From the results of powder sample measurement, the crystal structures were identified as the P6₃cm and Pbca structures at the intermediate-temperature (75<T<165 K) and lowest-temperature (T<68 K) phases, respectively. From the results of single-crystal measurement, it was clarified that Ising spins were arranged in an up-up-down-down manner with a triple-domain formation below the Néel temperature. Satellite peaks on the shoulder of magnetic peaks were observed near the Néel temperature.