Theoretical model for the magnetic structure of the tellurite sulfates Na2Cu5(TeO3)(SO4)3(OH)4 and K2Cu5(TeO3)(SO4)3(OH)4

Abstract

A theoretical model for two new tellurite sulfates, namely Na2Cu5(TeO3)(SO4)3(OH)4 and K2Cu5(TeO3)(SO4)3(OH)4, is determined to be compatible with ab initio calculations. The results obtained in this paper show that some previous speculations in the literature about the couplings are correct, obtaining a model with a mixture of ferromagnetic and antiferromagnetic couplings. We use a combination of numerical techniques to study the magnetic properties of the model. Our numerical calculations based on the density-matrix renormalization group method reveal that the system presents Ising-like magnetization plateaus at rational values of the saturation magnetization.