Growth of YBCO thin films on TiN(0 0 1) and CeO₂-coated TiN surfaces

Epitaxial growth of YBa₂Cu₃O_7-x (YBCO) layers on TiN(0 0 1) surfaces was explored, both with and without CeO₂ intermediate layers. The epitaxial TiN layers were grown on MgO(0 0 1) and textured Ni substrates. Thin CeO₂ (∼200 nm thick) and YBCO (∼300 nm thick) layers were grown on TiN-coated MgO substrates, using pulsed laser deposition. While YBCO grown directly on TiN was of poor quality, a good epitaxial YBCO layer was obtained using a thin CeO₂ cap layer on the TiN. A superconducting critical transition temperature (T_c) of 89 K was measured by AC susceptibility. The critical current density (J_c) was 6 × 10⁵ A/cm² obtained at 77 K by whole body transport current measurement in self-field using a 1 μV/cm criteria. These results suggest that transition metal nitrides, such as TiN, are potentially useful as buffer layers for YBCO thin films. Advantages of the nitride buffer layers compared to conventional oxide buffers include high electrical and thermal conductivity, better mechanical toughness, good diffusion barrier characteristics, and relative ease of deposition. Published by Elsevier Science B.V.