Optimization of BaZrO3 concentration as secondary phase in superconducting YBa2Cu3O7 for high current applications

Bilal A Malik,K Asokan,Manzoor A Malik

doi:10.1063/1.4948512

Bilal A Malik, K Asokan + Show 1 more

Open Access

https://doi.org/10.1063/1.4948512

Copy DOI

Abstract

We report the superconducting state properties of YBa2Cu3O7 (YBCO) on introduction of BaZrO3 (BZO) as a secondary phase. YBCO+xBZO (x= 0, 2, 4, 6, and 10 wt%) composite samples were prepared by solid state reaction method and characterized for structural, morphological and superconducting properties. X-ray diffraction confirms the increased crystallinity and images of scanning electron microscopy measurement show an increase in both grain size and grain connectivity on addition of BZO in YBCO. These effects are well pronounced in an applied magnetic field. Critical current density, JC, as well as the pinning force peaks at 4% of BZO concentration showed significant difference. A three-fold enhancement in JC and a six-fold enhancement in pinning force were observed at this optimum BZO concentration. This has been attributed to the pinning of flux lines in YBCO due to introduction of BZO as a secondary phase. These results show that this composite has potential application in high current applications.

Highlights

Soon after the discovery of superconductivity in cuprates, it became apparent that these materials can be tuned for high current applications.[1,2,3] for such applications, at high magnetic fields, several issues needed to be addressed
The presence of BZO in YBCO matrix is evident from the occurrence of extra peaks marked by (*) at 2θ = 30◦ and 2θ = 43◦ in the diffraction pattern whose intensity increases with increase of BZO concentration in YBCO
Based on the fact that BZO has an excellent lattice mismatch with YBCO, BZO when added as secondary phase in YBCO and prepared five samples (YBCO+ xBZO) with 0-10 wt.% BZO concentration

Summary

INTRODUCTION

Soon after the discovery of superconductivity in cuprates, it became apparent that these materials can be tuned for high current applications.[1,2,3] for such applications, at high magnetic fields, several issues needed to be addressed. Some of the major problems are: i) granular nature of cuprates resulting in large grain boundary area and weak links among grains, ii) exhibition of complete Meissner effect only up to lower critical field (HC1) beyond which vortices formation makes vortex dynamics complex These vortices move under the influence of transport current due to Lorentz force resulting in dissipation of energy. Since BZO has large lattice mismatch with YBCO (nearly 9%) its introduction develops strain between the phases leading to enhanced pinning These sub- micron sized BZO particles at grain boundaries apart from acting as strong pinning centers improve inter grain connectivity.[31] All these studies favour BZO as a most suitable material for introducing artificial pinning centers and thereby increasing JC. Five different concentrations were selected by varying from 2 to 10% of BZO in YBCO matrix and well-characterized for structure, morphology and superconducting properties

EXPERIMENTAL DETAILS

RESULTS AND DISCUSSIONS

CONCLUSION