Synthesis of in-plane aligned a-axis YBa2Cu3O7−δ thin films

We report the successful synthesis of superconducting YBa2Cu3O7−δ (YBCO) (100) thin films with alignment of the in-plane c axis. These films were grown on single crystal NdGaO3 (110) substrates. The twofold symmetry of the substrate surface is believed to lead to anisotropic alignment of the in-plane c axis of the epitaxial YBCO (100) film. X-ray diffraction studies indicate that over 80% of the film grew epitaxially with the YBCO [100] perpendicular to the substrate surface, and YBCO [001] aligned along one pseudo-cubic axis of the NdGaO3. The superconductivity onset of the film was measured to be 89 K by ac susceptibility.