Fabrication of GdBa2Cu3O7−δ films by photo-assisted-MOCVD process

• Photo-assisted MOCVD was employed to fabricate pure GdBCO films for the first time.
• With higher Ts, a-axis grains in films decreases and (0 0 1) orientation was enhanced.
• Growth rate and degree of texture formation were found to be influenced by Po2.
• Grain-boundary-free GdBCO films prepared by PhA-MOCVD are single-crystal-like.
• C-axis GdBCO with Jc of 2.5 MA/cm2 (77 K, 0 T) was obtained at Ts of 810 °C and Po2 of 4 Torr.

Pure GdBa2Cu3O7−δ (GdBCO) films were deposited on (1 0 0)-oriented LaAlO3 (LAO) substrates by photo-assisted metal organic chemical vapor deposition (PhA-MOCVD) technique. The effects of substrate temperature (Ts) and oxygen partial pressure (Po2) on microstructure, growth rate and superconducting critical current density (Jc) were investigated. A dense and no grain boundary visible, single-crystal-like cross-sectional morphology was observed. For the GdBCO film sample obtained at Ts of 810 °C and Po2 of 4 Torr, the full width at half-maximum were 0.08° and 0.41° for out-of-plane and in-plane orientations, respectively. Such low values were similar to that of single crystal GdBCO. Optimally processed GdBCO samples exhibited Jc of 2.5 MA/cm2 at 77 K in self-field. A relatively high growth rate of 0.104 μm/min for the GdBCO film is realized by the PhA-MOCVD technique.