In-situ patterned laser deposition of high-T_c Y-Ba-Cu-O superconducting thin films

Reliable critical current density measurements have been sucessfully carried out on superconducting thin films which were in situ patterned during the laser deposition process. This method does not require cumbersome wet etching or post-ion-implantation patterning steps for measuring transport critical current densities of thin films. Epitaxial films of YBa ₂Cu₃O₇ on (100) SrTiO₃ and (100)yttria-stabilized ZrO₂ (YSZ) were fabricated at low processing temperatures (500-650 °C) by the excimer laser ablation technique in an oxygen ambient coupled with a dc bias voltage of +300 V on an interposing ring between the substrate and the target. Steel masks of various lateral dimensions were placed close to the substrate to generate various patterns. The superconducting properties obtained at the masked and unmasked areas of the film were similar and reproducible. The thickness and width of the mask have been found to be critical in controlling the superconducting properties of the patterned thin films. Excellent quality superconducting thin films were obtained in the patterned areas. The critical temperature of the films was found to lie in the range of 88-90 K, and the best critical current density values (at 77 K and zero magnetic field) of 1.0×10⁶, 5.0×10⁶, and 6.5×10⁶ A/cm² were obtained for films deposited on (100) YSZ, (100) SrTiO₃, and (100) LaAlO₃, respectively.