Epitaxial CeO2 buffer layer on deliberately miscut sapphire for microcrack-free thick YBa2Cu3O7-δ films

• Published in: Journal of crystal growth 2005-11, Vol.284 (3-4), p.417-424
• Main Authors: NIE, J. C, YAMASAKI, H, NAKAGAWA, Y, DEVELOS-BAGARINAO, K, MURUGESAN, M, OBARA, H, MAWATARI, Y
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Cuprates superconductors (high tc and insulating parent compounds); Exact sciences and technology; Materials science; Methods of crystal growth; physics of crystal growth; Physics; Superconductivity
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2005.07.022

CeO2 buffer layers were grown on deliberately miscut Al2O3 (1 1 0 2) surfaces by pulsed laser deposition. Atomic force microscopy observations revealed that their morphology was very smooth. High lattice perfection of the CeO2 layer was shown by X-ray diffraction. Thick YBa2Cu3O7-delta (YBCO) films have been grown on such vicinal surfaces by laser ablation. The resultant YBCO films were stoichiometric and microcrack-free with a porous morphology (confirmed by scanning electron microscopy), consisting of interconnected islands and deep holes (pores). The porous feature is considered as one of the sources contributing to the strain-relieving mechanism responsible for the increase in film thickness without microcracking. Microcrack-free thick YBCO films revealed Tc = 90.5 - 0.5 K, Jc(77.3 K, 0 T) = 1.5 - 3.0 x 106 A/cm2, and a substantial enhancement of Jc x t(77.3 K, 0 T) up to 246 A/cm.