Magnetic Properties of Cu₃(TeO₃)₂Br₂ with Spin 1/2 Diamond Lattice

Abstract

Magnetic studies have been carried out on Cu₃(TeO₃)₂Br₂ with diamond lattice of spin 1/2 Cu²⁺ ions. By using the high temperature expansion of the magnetic susceptibility, the exchange coupling constants have been determined to be J₁⁄k_B=280±4 K (antiferromagnetic) and J₂⁄k_B=−23±1 K (ferromagnetic) for two kinds of Cu–Cu pairs formed by the connections with edge and diagonal lines of a diamond, respectively. It indicates that each diamond chain has the ferrimagnetic state in the reported phase diagram [Takano et al.: J. Phys.: Condens. Matter 8 (1996) 6405]. The observed magnetic behavior can be well understood by this characteristic. Because J₂ is ferromagnetic, the present system does not have magnetic frustration effects.