Anisotropy of g-factor of Cu2+ ion and Anisotropic exchange interaction between Spins in antiferromagnetic Bi2CuO4

To study the anisotropy of g-factor of Cu²⁺ ion in the antiferromagnetic Bi₂CuO₄ having an interesting crystal structure, we calculate the energy splitting of the orbital state of Cu²⁺ ion due to the electric crystalline field arising from the surrounding O²⁺, Bi³⁺ and Cu²⁺ ions. On the basis of Pryce's spin Hamiltonian we evaluate g-tensor of each Cu²⁺ ion in the unit cell. We also discuss the anisotropic exchange interaction which is important as the origin of the anisotropy energy for Cu²⁺ ion with S=1/2. The results are discussed in connection with observations.