As-grown Y-Ba-Cu-O superconducting thin films prepared by magnetron sputtering

YBa 2 Cu 3 O 7-δ thin films were prepared on MgO(001) planes at 600°C by RF magnetron sputtering. These as-grown films were classified into 3 types: high- T c , low- T c and nonsuperconducting. In this report, film properties are discussed in relation to the annealing effect in an oxygen atomosphere and lattice parameters (c o ). By optimizing the sputtering conditions, c-axis-oriented superconducting films with an endpoint T c above 80 K are obtained. These as-grown films are highly uniform and semi-transparent and have a room temperature resistivity of 0.3 mΩcm.