MOD multi-layer YBCO films on single-crystal substrate

摘要

Several practical applications require relatively thick Y1Ba2Cu3O7 (YBCO) coated conductors (1 -2 mu m) to carry a high critical current (I-c). However, as the thickness of the YBCO film increases, its critical current density (J(c)) decreases. In this work, we report the successful fabrication of thick YBCO films using a multiple coatings technique while maintaining a high Jc. In particular, several YBCO films with different numbers of layers were fabricated on a LaAlO3 substrate by a multiple coatings process using a trifluoroacetate metal organic deposition method (TFA-MOD). No cracks or pores were observed in cross-sectional transmission electron microscope (TEM) images of these films; further, the layers were well connected with the smooth interface. The majority of the grains in the films were c-axis oriented. Full-width at half-maximum (FWHM) values for in-plane and out-of-plane alignments for a five-layer film were 2.45 degrees and 1.2 degrees respectively. J(c) exceeding 1.6 MAcm(-2) and critical current (I-c) of 160 A cm(-1) have been obtained for a 1 mu m thick film with five layers at 77 K.