Table of Contents
International Journal of Superconductivity
Volume 2014, Article ID 768714, 7 pages
http://dx.doi.org/10.1155/2014/768714
Research Article

Electrical Transport and Lowered Percolation Threshold in YBa2Cu3O7−δ-Nano-YBa2ZrO5.5 Composites

Electronic Materials Research Laboratory, Department of Physics, Mar Ivanios College, Thiruvananthapuram, Kerala 695015, India

Received 10 May 2014; Accepted 6 August 2014; Published 25 August 2014

Academic Editor: Dong Qian

Copyright © 2014 Pullanhiyodan Puthiyaveedu Rejith et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We investigated the chemical reactivity and percolation characteristics of insulating nanocrystalline YBa2ZrO5.5 prepared by modified combustion route and the YBa2Cu3O7−δ superconductor composite system. Structural analysis was done by using X-ray diffraction technique, surface morphology of the samples was studied using scanning electron microscopy, and electrical transport measurements like critical transition temperatures () and self-field transport critical current () were done by using standard four-probe technique. It is found that, in YBa2Cu3O7−δ-nano-YBa2ZrO5.5 composite system, the superconductor and insulator materials coexist as separate phases without any noticeable chemical reaction even after sintering at high temperatures. Furthermore, percolation threshold and critical exponent are found to be , and . And the analysis of the current flow in the polycrystalline samples reveals weak link behavior in the majority of grain connections.