Features of phase separation in the spin-pseudospin model

Reviewed model spin-pseudospin, which simulate the plane CuO2 in сuprates and take into consideration spin exchange and charge correlations on the site and between sites. Model spin-pseudospin allows us to study the competition of charge and magnetic ordering on plane CuO2 in cuprate. In this paper, we evaluated the effect of this competition exploring the stability of the thermodynamic system for reasonable parameters of the model. For this studie, we calculated such values as we call it the compressibility of our system and chemical potential, then we compared results of a numerical calculation using classical method Monte-Carlo with analytical results within the mean-field approximation.