Cu, Pu and Fe high Tc superconductors: Spin holes in anti-ferromagnetic clusters form nonmagnetic bipolarons

The new iron based high Tc superconductors with Tc up to 55 K have stirred new interest in this field. It is consensus that the BCS mechanism is not able to explain the high Tc's. In the following we propose that spin holes in anti-ferromagnetic clusters combine to make nonmagnetic bipolarons, which can condense and lead to superconductivity.