The impact of preparation condition and Li substitution on Bi2-x LixPb0.3 Sr2Ca2Cu3O10+ δ Compound

Other Title(s)

تأثير ظروف التحضير و التطعيم بالليثيوم على المركب Bi2-x LixPb0.3Sr2Ca2Cu3O10+ δ

Dissertant

Rauf, Nadin Qahtan

Thesis advisor

Abbudi, Sad Farhan
Abbas, Muna Musa

University

University of Baghdad

Faculty

College of Science

Department

Department of Physics

University Country

Iraq

Degree

Master

Degree Date

2014

English Abstract

Solid state reaction method was used to prepare high temperature superconductor with a nominal composition Bi2-x LixPb0.3Sr2Ca2Cu3O10+δ for( x=0,0.1,0.2,0.3,0.4, and 0.5).

The effect of preparation conditions and Li substitution on Bi-(2223) phase has been investigated by X-ray diffraction, scanning electron microscope(SEM), resistivity measurements and oxygen content to obtain the optimum conditions for the formation and stabilization of the high critical temperature( Tc )phase.

Preparation conditions required to obtain the high-Tc Bi(2223) phase have been taken in to consideration via sintering temperature and sintering time.

Four groups of samples were prepared for each superconducting compound in order to study the effect of preparation conditions and sintering temperature that needed to increase the volume fraction of the high –Tc phase .

The first group was sintered at 830°C for 140hr (one step), the second group was sintered at 840°C for 140hr (one step), the third group was prepared by applying conditions consisted of three steps, first step the samples were sintered at 850°C for 50hr , in the second step the samples were regrind and pressed at 0.7 GPa and then sintered at 850°C for 50hr, in the third step the samples were sintered at 830°C for 40hr.

While in the fourth group the whole process that had been used to prepare the third group was repeated at 860°C but melted samples were obtained.

It has been found that the third group are optimum conditions of producing high-Tc phase, the highest critical temperature value is found for the highest value of oxygen content with x=0.3was Tc =130K.

The X-ray analyses for all superconducting samples showed an orthorhombic structure with two phases, high-Tc(2223) phase and low-Tc(2212) phase in addition to that an impurity phase was found.

Furthermore, it was found that the lattice constants a and c experienced a random variation with the increase of Li content.

Scanning electron microscope (SEM) has been used to identify the morphology of the superconducting phase .The plate –like grains of the low Tc (2212)and high (2223) phases appeared in all micrographs of the superconducting samples ,and thin elongated grain with no preferred orientation characterize the microstructures was obtained.

Main Subjects

Physics

No. of Pages

79

Table of Contents

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Language

English

Data Type

Arab Theses

Record ID

BIM-607425