1,2,4-Triazole Complexes VIII *

Abstract

Co(trz)2(NCS)2 has been investigated by means of magnetic susceptibility and magnetization measurements on single crystals in the temperature range from 1.1 - 300 K, heat capacity measure­ments from 1.5 - 90 K, neutron powder diffraction at 1.2 K and ESR measurements on the Co­doped Zn compound at 9 K. The compound appears to have two-dimensional structural and mag­netic properties. A transition to an antiferromagnetically ordered state takes place at Tc = 5.71 (1) K. Susceptibility measurements along the three orthorhombic axes reveal a strongly anisotropic character. The b axis is found to be the preferred axis of antiferromagnetic alignment. The susceptibility data along b and the heat capacity results are in good agreement with the predictions for the quadratic layer, S=½, XY antiferromagnetic, with an intralayer exchange constant j/k= -5.0(1)K. Below Tc the field dependent behaviour of the magnetization and the susceptibility along the a axis exhibits a transition at ~ 1 kOe. Hidden canting is found to be present. The magnetic structure can be described by four sublattices with the magnetic moments lying in the a-b plane along directions that are at an angle of 7° with the b axis.