Reentrant antiferromagnetism in oxygen-doped cuprates

The reentrant behavior of the sublattice magnetization in the doped cuprates La2CuO4+x and YBa2Cu3O6+x is explained by a model which assumes that the localized holes reduce the sublattice magnetization more strongly than the mobile holes. Good agreement with the experiments is obtained, using the measured temperature dependence of the localized hole density, which is characterized by the (measurable) hole excitation energy E(x), and the difference between mobile and localized holes, described by a single x-dependence parameter. The theory also accounts for the absence of the reentrant behavior in highly doped samples. At higher temperatures we find additional corrections, due to a renormalization of the spin waves by the impurities.