I n s i t u grown YBa2Cu3O7−d thin films from single-target magnetron sputtering

Using single-target off-axis sputter deposition, high quality superconducting films of YBa2Cu3O7−δ were made in situ. These films have properties which are distinctly different from those of bulk ceramics and of post-deposition annealed films. Their superconducting resistive transitions remain sharp regardless of the value of Tc between 75 and 86 K. Normal-state conductivities are as high or higher than the best single crystals. Critical current densities as high as 6×107 A/cm2 at 4.2 K. Tc (R=0) falls off with film thickness down to 10 K for 35–40 Å films. All of the above properties are relatively insensitive to compositional variation. The results can be explained if the in situ growth results in well-formed CuO2 planes with defects occurring elsewhere.