Preparation of a high-j_c Y-Ba-Cu-O film at 700 °C by thermal chemical vapor deposition

A high-J_c Y-Ba-Cu-O superconducting film was successfully prepared at 700 °C on a SrTiO₃(100) single-crystal substrate without postannealing by thermal chemical vapor deposition under a low-oxygen partial pressure of 0.036 Torr in the total gas introduced into a hot-wall-type reactor (total gas pressure: 10 Torr), using 1% O₂ balanced with Ar as a reactant gas. The sources for the elements of Ba, Y, and Cu were β-diketone metal chelates. The film mainly consisted of YBa ₂Cu₃O_x with c-axis orientation perpendicular to the substrate plane and included small amounts of a-axis oriented and randomly oriented grains. The film showed the superconducting transition temperature defined by zero resistivity at 89 K. The critical current density based on a 2 μV/cm criterion was 2.2 × 10⁶ A/cm² at 77.3 K and 0 T.