Introduction of Nano Ceria into Infiltration Growth Processed YBCO Superconducting Composites

Abstract

Introduction of nanoparticles as flux pinning centers in yttrium barium copper oxide (YBCO/Y-123) superconductors has been extensively explored in order to improve high field current-carrying capabilities. A uniform distribution of these nanodopants throughout the superconducting matrix is the most essential and desirable. The present work provides a nonconventional approach of introducing nanoparticles into YBCO superconductors by introducing nanoparticles in Y₂BaCuO₅ (Y-211) preform and then subjecting the preform to infiltration and growth process. The Y-211 preform containing 2 wt.% ceria nanoparticles of the order of 60 nm is referred to as Ce-2 preform. The microstructure of Ce-2 preform shows a uniform distribution of nanoparticles without much interaction even to a temperature of 950 °C. At a higher concentration, a mild interaction was observed which in a way aided in keeping the nanoparticles firmly attached to Y-211 particles. Superconducting transition temperature (T _c) of Ce-2 has reduced to 86 from 92 K of pure YBCO with a broad transition. Microstructures of Ce-2 composite suggest strong interaction of ceria nanoparticles with Y-211 as well as with liquid phases which resulted in the formation of fine particles of BaCeO ₃ of the order of 200 nm, which has been observed by many investigators. It is possible that some amount of ceria might have entered into a superconducting matrix which can reduce T _c as reported earlier. The presence of low T _c phase along with a large number of fine particles have improved critical currents densities (J _c ) to a field of 9 T at 65 K. The present approach has demonstrated substantial improvement in J _c at high fields at the expense of low and broad T _c. ∖AuthQuery{Q2}{The sentence “The present approach provides a scope for detail study on reaction mechanisms and infiltration process in IGP with nanoparticles” was modified to “The present approach provides a scope for detailed study on reaction mechanisms in infiltration and growth process (IGP) with nanoparticles.” Please check if the edit made appropriately retains the intended meaning of the sentence.}The present approach provides a scope for detailed study on reaction mechanisms in infiltration and growth process (IGP) with nanoparticles.