Abstract
The effect of nano-size ZrO2 powder addition on the microstructure and superconducting properties of Y–Ba–Cu–Osingle grain bulk superconductors has been investigated. Significant pushing phenomena ofY2BaCuO5 (Y-211) particles,particularly in the c growth sector, were observed even with a small amount ofZrO2 added to the precursor powder. An increase in Y-211 particle pushing was observed with increasingZrO2 content, leading to an inhomogeneous bulk microstructure. In addition, agrowth cycle consisting of a Y-211 free layer–porous narrow layer–Y-211high concentration layer was observed for samples prepared with 0.25 wt%ZrO2 in boththe a and c growth sectors. The extent of the growth of single grain Y–Ba–Cu–O (YBCO) decreased with increasingZrO2 content due to increased pushing of Y-211 particles towardsmolten liquid. The superconducting transition temperature,Tc, ofthe ZrO2 containing YBCO samples was sharp but depressed slightly (by up to 1 K)compared with an undoped YBCO grain, indicating a relative insensitivity ofTc toZrO2 content. Finally, the sensitivity of critical current density,Jc, to applied magnetic field in large grain bulk YBCO containingZrO2 was observed to depend critically on position due to the inhomogeneous samplemicrostructure.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call