Dissertation/Thesis Abstract

Synthesis, P-T phase diagram, and TC of R2Ba4Cu7O15 (R = Dy, Y, DyY, GdY)
by Sabok-Sayr, Seyed Ahmad, M.S., Northern Illinois University, 2012, 74; 1519751
Abstract (Summary)

Phase stability study of R2Ba4Cu7 O15 (247, R=Dy,Y, Er, DyY, GdY, and EuY) have been done for superconducting wire development. The oxygen pressure - temperature phase diagrams of R2Ba4Cu7O 15 superconductors have been investigated in the temperature range between 850 and 1025 °C and the pressure range between 1 and 50 atm. O2. The relative fraction of the phases: RBa2Cu3O7 (123), RBa2Cu4O8 (124), and 247, was determined by studying the intensity of the x-ray diffraction peaks of each phase. The condition at which the phase pure 247 exists was determined to be P = 10 atm. and T = 1025 °C. Under these conditions samples with larger size R = LaY, NdY, SmY, and Eu did not form pure 247 phase. Annealing at P = 200 atm. O2 and 400 °C was used to increase oxygen content of the as-synthesized materials and to induce superconductivity. The highest transition temperatures of 70 K were observed for R=Y compositions.

Indexing (document details)
Advisor: Dabrowski, Bogdan
Commitee: Brown, Dennis E., Chmaissem, Omar, Dabrowski, Bogdan
School: Northern Illinois University
Department: Physics
School Location: United States -- Illinois
Source: MAI 51/03M(E), Masters Abstracts International
Subjects: Condensed matter physics
Keywords: Dysprosium, Gadolinium-yttrium, Rare earth barium copper oxide, Yttrium
Publication Number: 1519751
ISBN: 9781267658661
Copyright © 2019 ProQuest LLC. All rights reserved. Terms and Conditions Privacy Policy Cookie Policy