Critical parameters in the sputter-deposition of NdBa2Cu3O7-delta thin films

A superconducting thin film of NdBa2Cu3O7-delta (NBCO) was prepared on an M gO(100) substrate by de magnetron sputtering. Superconducting properties as well as features such as resistivity at room temperature and surface morph ology were improved by optimizing the composition of sputtering target and critical parameters such as substrate temperature and oxidation gas pressur e. A highly c-axis oriented thin film with T-c (zero resistance temperature ) = 95.2 K was obtained reproducibly with NdBa2Cu3.2O7-delta off-stoichiome tric target sputtering. T-c = 95.2 K was 8 K higher than that deposited by stoichiometric target sputtering. Critical current density was 1 x 10(6) A cm(-2) at 77 K, and surface roughness was 35 nm.