Thermogravimetric, thermopower, and electrical conductivity studies of the Ba₂YCu₃O₇₋ₓ system

Author

C. John Brannon

Abstract

"The Ba₂YCu₃O_7-x system was investigated using thermogravimetric, thermopower, and d.c. electrical conductivity techniques. The system was found to exhibit a semiconductor to metallic transition coincident with the documented orthorhombic to tetragonal phase transition. Conduction is accomplished in the semiconducting phase by an activated small hopping polaron mechanism. The oxide was observed to be a p-type semiconductor over the temperature and oxygen activity ranges studied.

The conductivity, carrier concentration, and mobility behaviors of the oxide are primarily functions of its oxygen content. All three properties exhibited only a slight temperature dependence. The carrier concentration is essentially constant at a given oxygen content. The carrier concentration ranged from about 0.5 x 10²¹/cm³ at 800°C and O = 6.3 to 6 x 10²¹/cm³ at 500°C and O = 6.95. Mobilities ranged from about 0.05 cm²/V sec. at 600°C and O = 6.4 to 0.5 at 800°C and O = 6.7"--Abstract, page ii.

Advisor(s)

Anderson, H. U. (Harlan U.)

Committee Member(s)

Moore, Robert E., 1930-2003
Ownby, P. D.
Guha, Jyoti, P.
Sparlin, Don M.
Pringle, Oran Allan

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Ceramic Engineering

Sponsor(s)

United States. Department of Energy

Publisher

University of Missouri--Rolla

Publication Date

Spring 1989

Pagination

viii, 122 pages

Note about bibliography

Includes bibliographic references (pages 104-114).

Rights

© 1989 C. John Brannon, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Thesis Number

T 5863

Print OCLC #

20900371

Electronic OCLC #

1091902652

Link to Catalog Record

Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.

Recommended Citation

Brannon, C. John, "Thermogravimetric, thermopower, and electrical conductivity studies of the Ba₂YCu₃O₇₋ₓ system" (1989). Doctoral Dissertations. 714.
https://scholarsmine.mst.edu/doctoral_dissertations/714