Investigation of in-plane orientation characteristics for Bi-2212/MgO thin films fabricated by the MOD method

We investigated the characteristics of in-plane orientation for c-axis-oriented Bi-2212 thin films on MgO substrates, fabricated by the metal–organic decomposition (MOD) method. Bi-2212/MgO films were annealed using a 2-step heat treatment. The dominant rotation angle of the Bi-2212 film was 45° ([1 0 0] of Bi-2212 // [1 1 0] of MgO) for a precursor film fabricated at 500 °C and fired at 840 °C for 0 min or 30 min. However, after firing for 1 h the ϕ-scanning signal indicating the 45° angle became smaller and the signal representing an angle of about ±12° ([1 0 0] of Bi-2212 // [5 1 0] of MgO) became larger. After firing for 3 h, this ±12° signal became dominant. The extent of the 45° angle’s shift to ±12° increased with increasing firing time. On the other hand, when the precursor film was fabricated at 430 °C, signals indicating angles of 0°, ∼±12°, and 45° were observed after firing for 30 min. The rotation angle depended on the precursor-fabrication temperature when the precursor film was fired at 840 °C for 0 min or 30 min.