Magnetic properties of Cu3(TeO3)2Br2 with spin 1/2 diamond lattice

Magnetic studies have been carried Out on CU3(TeO3)(2)Br-2 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 J(1)/k(B)=280 +/- 4 K (antiferromagnetic) and J(2)/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 1) is ferromagnetic, the present system does not have magnetic frustration effects.