Atomically flat MOD La₀.₇Sr₀.₃MnO₃ buffer layers for high critical current YBa₂Cu₃O₇ TFA films

Abstract

Superconducting YBa₂Cu₃O₇ (YBCO) thin films were grown by the trifluoroacetates route onto metallorganic deposited La₀.₇Sr₀.₃MnO₃ (LSMO) buffer layers. The growth conditions of the LSMO films have been studied in detail and fully strained epitaxial layers with atomically flat surfaces have been obtained with local roughness ∼1 nm, as determined by atomic force microscopy. We prove that this surface morphology is a key parameter for achieving YBCO/LSMO multilayers with high critical current densities in self-field, J sf c (77 K) = 1.8 MA cm−². Angular pinning studies demonstrate that the defect structure is modified with respect to standard TFA–YBCO films as a pronounced peak in Jc is observed for H c at high temperatures. This indicates the presence of anisotropic defects playing an important role in vortex pinning even at the irreversibility line stressing the suitability of these all-chemical TFA–YBCO/LSMO multilayers as conductive coated conductor architectures.