Influence of addition of nanosize barium cerate on the microstructure and properties of top‐seeded melt growth YBCO bulk superconductors
P. Diko, Renáta Pagáčová, K. Zmorayová, Veronika Kuchárová, Liudmila Vojtková, V. Antal, V. Kavečanský
Abstract
Abstract Barium cerate (BaCeO 3 ) is one of the possible additions to bulk YBa 2 Cu 3 O 7 single‐grain superconductors to suppress the growth of Y 2 BaCuO 5 (Y211) particles. This paper investigates the synthesis of barium cerate powder and its use in YBa 2 Cu 3 O 7 bulk superconductors. Crystalline barium cerate was synthesized by solid‐state reaction, by co‐precipitation of oxalates and by sol‐gel method. Final calcination was held in air or in vacuum. It is shown that the most efficient in refining Y211 is nanocrystalline barium cerate prepared by sol‐gel method calcined in vacuum. The effective refinement of Y211 particles occurred over the entire interval of nanocrystalline BaCeO 3 addition from 0.38 to 1.90 wt%. The optimal concentration of nanosize barium cerate was determined, microstructure and superconducting properties were characterized. The effect of Y211 content on trapped field in YBCO bulks with addition of nanocrystalline barium cerate is shown.