Direct deposition of YBCO on polished Ag substrates by pulsed laser deposition

YBCO thin films were directly deposited on mechanically polished nontextured silver (Ag) substrates at elevated temperature by pulsed laser deposition with various inclination angles of 35degrees, 55degrees, and 72degrees. Strong fiber texture, with the c-axis parallel to the substrate normal was detected by X-ray diffraction pole figure analysis. Atomic force microscopy and scanning electron microscopy images revealed that a few a-axis-oriented grains were dispersed on the top surface of the YBCO films. Transmission electron microscopy revealed dense amorphous layer at the interface between the YBCO film and the Ag substrate. Energy dispersive spectrum analysis indicates that the YBCO film deposited on the Ag substrate is slightly Cu-deficient. A YBCO film deposited at 755 degreesC and an inclination angle of 55degrees exhibited T-c = 90 K. Transport critical current density measured by the four-probe method at 77 K in self-field was approximate to2.7 x 10(5) A/cm(2). This work demonstrated a simple and inexpensive method to fabricate YBCO-coated conductors with high critical current density. (C) 2002 Elsevier Science B.V. All rights reserved.