Abstract
We propose a new model of impurity center formed by a cathion substitute for Cu, like Zn, in CuO2 planes. Its main effect on superconducting electrons is due to the non-zero exchange field on O sites, neighbors to (non-magnetic) impurity. We discuss a strong suppression of the d-wave order parameter, a zero-energy resonance in the local density of states, and spin polarization of charge carriers, which can be related to the experimentally observed effects in Zn-doped copper oxides. These results are obtained without using the widely accepted unitary scattering limit.