The effect of composition and oxygen pressure on the superconducting properties of NdBa2Cu3O7-x thin films, deposited by rotatable magnetron sputtering

Rotatable magnetron sputtering is still a promising technique for scaling up of large area deposition of high temperature superconducting thin films. Furthermore, it represents a standard equipment for very large area web coating and glass coating in industrial environment. We have already demonstrated that with rotatable magnetron sputtering epitaxial c-axis oriented NdBa₂Cu₃O_7-x (NBCO) thin films could be obtained on MgO and YSZ single crystals and buffered tapes. The superconducting properties, like T_c and J_c, of these films are still reduced due to low pressure sputtering. The c-axis lattice parameter is expanded or the sputtered NBCO thin film exists of 2 phases, one with the correct c-axis parameter and the other phase shows an elongated c-axis parameter, which influences the superconducting properties. In this work we will investigate the properties of thin films, sputtered with a nonstoichiometric target at low pressure (classical sputter regime). Especially, the influence of the oxygen partial pressure is very important and will be studied.