Estimation of the doping dependence of the Néel temperature in high-Tccopper 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 spectrum and the staggered magnetization at nonzero temperature near the transition to the disordered phase. The incoherent part of the charge spectrum mainly contributes and leads to an estimate of the doping-dependent Néel temperature which turns out to be in fairly good agreement with experiment for high-${\mathit{T}}_{\mathit{c}}$ copper oxides.