Influence of the microstructure of the SrTiO3 buffer layer on the superconducting properties of YBa2Cu3O7-x films

We prepared a SrTiO3 (STO) buffer layer with various surface morphologies a nd deposited YBa2Cu3O7-x (Y-123) films on the buffer layer. From the result of four-probe resistance measurements, the maximum T-c, (90 K) was obtaine d for the Y-123 film deposited on the buffer layer with larger grain size ( 2000 Angstrom) with good reproducibility. This indicated that the surface g rains of the buffer layer influenced the growth mechanism of Y-123 films. F urthermore, the STO buffer layer with larger grains and flatter surface wer e prepared on the STO layer deposited by pulsed laser deposition (PLD) on M gO substrate. (C) 2001 Elsevier Science B.V. All rights reserved.