Magnetic characteristics of superconducting REBa2Cu3O7-8 crystals

Date of Publication

2002

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Physics

Subject Categories

Physics

College

College of Science

Department/Unit

Physics

Thesis Adviser

Reuben Quiroga

Defense Panel Chair

Edgar Vallar

Defense Panel Member

Benjamin Chan
Emmanuel Rodulfo
Julius Maridable
Joseph Scheiter, FSC.

Abstract/Summary

A deeper understanding of high-Tc superconductivity can be provided by an investigation of the intrinsic properties of superconductors. With this motivation, the magnetic characteristics of superconducting REBa2Cu307-8 (RE, or rare earth= yttrium, neodymium) crystals is the focus of this thesis. High purity, high quality single YBa2Cu307-8 (YBCO) crystals were grown via a flux method. The irreversibility lines, pinning energies and critical current densities were determined using ac susceptibility and relaxation measurements. The effect of the presence of twins in these crystals was also studied. Melt processed intergrowth Nd1/2Y1/2Ba2Cu307-8 (Nd/Y)BCO) crystals (with 3 percent (Nd/Y)2BaCu05) were also fabricated for comparison of the effect of doping on the magnetic properties of high Tc superconductors. The empirical relation Hdc=K was obtained for the irreversibility lines (IL) of these clean crystals accounting for the simultaneous dependence of IL on the ac field amplitude and frequency.

Abstract Format

html

Language

English

Format

Print

Accession Number

TG03254

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

283 leaves ; 28 cm.

Keywords

Superconductors--Magnetic properties; Flux pinning; Superconductivity; Crystals

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