Dielectric properties of (Zn) x /CuTl-1223 nanoparticle-superconductor composites

M Mumtaz,K Nadeem,Abdul Jabbar,Shoaib Azeem,G Hussain,Saad Ullah,M W Rabbani,Liaqat Ali

doi:10.1007/s40145-016-0185-1

Abstract

Zinc (Zn) nanoparticles and (Cu0.5Tl0.5)Ba2Ca2Cu3O10−δ (CuTl-1223) superconducting phase were prepared separately by sol-gel and solid-state reaction methods, respectively. Zn nanoparticles were added in CuTl-1223 superconducting matrix with different weight percentage during the final sintering process to obtain (Zn) x /CuTl-1223 (x = 02-4 wt%) nanoparticle-superconductor composites. The effect of Zn nanoparticles on structural, morphological, superconducting, and dielectric properties of CuTl-1223 phase was investigated. The addition of these Zn nanoparticles has not affected the crystal structure of host CuTl-1223 superconducting phase. Superconducting properties were enhanced after the addition of Zn nanoparticles up to certain optimum content (i.e., x = 1 wt%), which were due to improved inter-grain connectivity by healing up of micro-cracks and reduction of defects like oxygen deficiencies, etc. The activation energy (U) was increased after the addition of Zn nanoparticles in CuTl-1223 phase. The dielectric properties of these samples (i.e., dielectric constant, dielectric loss) were determined by experimentally measured capacitance (C) and conductance (G) as a function of frequency at room temperature. The addition of metallic Zn nanoparticles in CuTl-1223 matrix has overall suppressed the dielectric parameters of (Zn) x /CuTl-1223 nanoparticle-superconductor composites. The metallic Zn nanoparticles played a significant role in inter-grain couplings by filling the voids and pores.

Highlights

One of the most eminent phase of (Cu1 xTlx)Ba2Can 1 CunO2n+4 δ (n = 2, 3, 4, ...) high temperature superconducting family is (Cu0.5Tl0.5)Ba2Ca2Cu3O10 δ (CuTl-1223) [1]
In CuTl-1223 phase, the charge reservoir layer (Cu0.5Tl0.5)Ba2O4 δ consists of Tl3+, Cu2+, and Ba2+ ions, which can localize the charge carriers, while the conducting CuO2 plane consists of mobile charge carriers
The charge reservoir layer, inter-grain boundaries, and micro-cracks act as dielectric media, which can be polarized by the displacement of charge carriers with the assistance of an external electric field from their equilibrium position

Summary

Introduction

These composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature-dependent resistance measurements, and dielectric properties. These peaks correspond to CuTl-1223 phase with lattice parameters a = 4.01 Å, Zn nanoparticles www.springer.com/journal/40145

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