Preparation of Ba ₂ YCu ₃ O 7‐δ Thin Films with Preferred Orientation through an Organometallic Route

Superconducting Ba 2 YCu 3 O 7‐δ thin films were prepared through an organometallic route. Single‐phase Ba 2 YCu 3 O 7‐δ thin films with preferred orientation were successfully prepared on SrTiO 3 (100) single‐crystal substrates at 800°C by a dip coating method using partially hydrolyzed Ba‐Y‐Cu organometallic solutions. Preferentially oriented Ba 2 YCu 3 ‐O 7‐δ thin films were also prepared on MgO (100) substrates. By controlling the partial hydrolysis conditions, a coating solution for precursor thin films was kept accurately at the stoichiometric composition. The use of ozone gas during the pyrolysis of the precursor thin films was found to suppress the formation of BaCO 3 . Ba 2 YCu 3 O 7‐δ thin films with c ‐axis orientation perpendicular to a SrTiO 3 (100) substrate, which were heat‐treated at 900°C for 15 min, exhibited a superconductivity transition with an onset of 90 K and an end of 75 K.