Solution-derived YBa_2Cu_3O_7 nanocomposite films with a Ba_2YTaO_6 secondary phase for improved superconducting properties

摘要

We report on the spontaneous segregation of double perovskite Ba_2YTaO_6 (BYTO) nanoparticles within YBa2Cu3O7 (YBCO) films forming a nanocomposite with two ternary oxides by the low cost and scalable chemical solution trifluoroacetate approach. Phase orientation, nanostructural and pinning studies are carried out by 2D x-ray diffraction, advanced scanning transmission electron microscopy and transport measurements, respectively. In this complex oxide nanocomposite system (YBCO–BYTO) the majority of the nanoparticles segregated within the (00l)-oriented superconducting matrix are randomly oriented. The presence of randomly oriented nanoparticles plays a key role in the generation of localized highly strained areas within the YBCO matrix which are suggested to strongly affect the superconducting properties. The incorporation of 6–10% of BYTO resulted in a maximum pinning force, at 77 K, three times higher than that obtained for a pristine sample, while T_c was maintained at 89–90 K.