ESTIMATION OF THE DOPING DEPENDENCE OF THE NEEL TEMPERATURE IN HIGH-T-C COPPER OXIDES

Using the polaron model as an approximation of the t-J model, we have computed in the two-time Green's-function formalism the spin-wave spec trum and the staggered magnetization at nonzero temperature near the t ransition to the disordered phase. The incoherent part of the charge s pectrum mainly contributes and leads to an estimate of the doping-depe ndent Neel temperature which turns out to be in fairly good agreement with experiment for high-T-c copper oxides.