Preparation and characterization of Y Ba₂ Cu₃ 0₇ high-T superconductor

(1991) Preparation and characterization of Y Ba₂ Cu₃ 0₇ high-T superconductor. Masters thesis, King Fahd University of Petroleum and Minerals.

[img]
Preview
PDF
10294.pdf

Download (4MB) | Preview

Arabic Abstract

-

English Abstract

Superconductor samples of Yba₂Cu₃O₇₋x were prepared by two different methods. Measurements using XFD, SEM, EPMA, and four probe method indicated single phased samples with orthorhombic structure and transition temperature of 92 K. Samples were further studied by XPS and UPS techniques, where representative clean surfaces were prepared by in-situ scraping. Valence band spectra show low density of states at Fermi level and strongly hybridized 0 2p and Cu 3d states. The position, shape, and satellite emission of Cu 2p indicate a mixture of Cu¹⁺ and Cu²⁺ valencies. The O 1s two components are intrinsic and the 531 eV peak is related to oxygen hole states (O₋). Ba core levels show a two component structure, suggesting two principal Ba-O configurations due to oxygen vacancies. The position and shape of Y doublets indicate weak Y-0 interactions. Annealling in UHV causes an increase in O² vacuncies and a reduction of Cu²⁺ valency. Water exposure causes the formation of hydroxides at the surface, while oxygen exposure has no significant effect.

Item Type: Thesis (Masters)
Subjects: Physics
Divisions: College Of Sciences > Physics Dept
Committee Advisor: Dabbousi, O. B.
Committee Members: Salim, M. A. and Avci, R. and Khawaja, E. E. and Hallak, A. B. and Hussain, Z.
Depositing User: Mr. Admin Admin
Date Deposited: 22 Jun 2008 17:01
Last Modified: 01 Nov 2019 16:59
URI: http://eprints.kfupm.edu.sa/id/eprint/10294