Resistivity-temperature characteristics of Y-deficient YBCO thin films derived by TFA-MOD method

Y-deficient Y1-xBa2Cu3O7-sigma films(x = 0, 0.05, 0.1) are fabricated on LaAlO3 (0 0 1) single crystal substrates using trifluoroacetate-based metalorganic deposition (TFA-MOD). X-ray diffraction patterns show that all films are highly c-axis oriented. The measurement of the resistance transition broadening under the applied magnetic field perpendicular to the surfaces of YBCO films indicates that a slight Y-deficiency (Y0.95Ba2Cu3O7-sigma) in YBCO films is favorable to improve flux pinning. However, a further increasing of Y-deficiency (Y0.9Ba2Cu3O7-sigma) leads to the degeneration of flux pinning abilities. The improvement of flux pinning may be related to the BaCuO2 phase particles with submicrometer scale or the defects induced by slight Y-deficiency. (C) 2004 Elsevier B.V. All rights reserved.