MOD multi-layer YBCO films on single-crystal substrate

Abstract

Several practical applications require relatively thickY1Ba2Cu3O7 (YBCO) coatedconductors (1–2 µm) to carrya high critical current (Ic). However, as the thickness of the YBCO film increases, its critical current density(Jc) decreases. In this work, we report the successful fabrication of thickYBCO films using a multiple coatings technique while maintaining a highJc. In particular, several YBCO films with different numbers of layers were fabricated on aLaAlO3 substrate by a multiple coatings process using a trifluoroacetate metal organic depositionmethod (TFA-MOD). No cracks or pores were observed in cross-sectional transmissionelectron microscope (TEM) images of these films; further, the layers were wellconnected with the smooth interface. The majority of the grains in the films werec-axis oriented. Full-width at half-maximum (FWHM) values forin-plane and out-of-plane alignments for a five-layer film were2.45° and1.2° respectively.Jc exceeding1.6 MA cm−2 and criticalcurrent (Ic) of160 A cm−1 have beenobtained for a 1 µm thick film with five layers at 77 K.