Magnetic Structures of Co₂TeO₃Cl₂

Abstract

Measurements of the magnetization and specific heat have been carried out for Co₂TeO₃Cl₂ with a sawtooth lattice having two crystallographically distinct Co²⁺ sites. A powder neutron diffraction study has revealed that two magnetic transitions take place at T_N1∼73 K and T_N2∼15 K. Below T_N1, Co spins at the apical sites of the sawtooth lattice order antiferromagnetically with their directions parallel to the b-axis. Co spins at the basal sites order antiferromagnetically at T_N2 with their directions canted in the ab-plane from the a-axis by Dzyaloshinski–Moriya interaction. At this transition, no change in the spin structure at the apical sites has been observed. Discussion on possible origins of these complicated spin structure is presented.