Self-consistent calculation of magnetization in oxide superconductors.

Abstract

In this paper we have calculated the magnetization as function of temperature for oxide superconductors. We have used the three-dimensional Heisenberg model introducing the anisotropy between the antiferromagnetic (AF) exchange coupling constant in the Cu-O plane and perpendicular to the plane. The Green's function method is used to evaluate the magnetization. In the random-phase approximation one gets a self-consistent expression for the magnetization. Using this expression we have calculated the magnetization self-consistently as a function of temperature and have compared our theoretical results with experiments. Good agreement between our theory and experiments are found throughout the temperature range. The parameters used in the calculation are [ital J][sub [ital a][ital b]]=120 meV and [ital J][sub [ital c]]=3.00[times]10[sup [minus]5][ital J][sub [ital a][ital b]]. Here [ital J][sub [ital a][ital b]] and [ital J][sub [ital c]] are the AF coupling constant in the Cu-O plane and perpendicular to the plane, respectively. The values of these parameters are consistent with the values reported in the literature. The role of the interlayer coupling [ital J][sub [ital c]] on the magnetization has been investigated.