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Title: Oxygen concentration effect on T/sub c/ of the Bi-Ca-Sr-Cu-O superconductor

Abstract

The T/sub c/ of Bi/sub 2/-Ca-Sr/sub 2/-Cu/sub 2/-O/sub 8-//sub x/ can be shifted reversibly over a rangel of at least 15 K by changing the oxygen concentration. T/sub c/ shifts downward for increased oxygen content. This is opposite to the shift seen in YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ and may be caused by reduction in the Fermi level reducing conductivity in the Bi-O layers. Oxygen concentration is varied by treatment in O/sub 2/ at appropriate pressures. The highest T/sub c/ = 78.5 K of the ''80-K'' phase is obtained by treating at 600 /sup 0/C in 10/sup -2/-bar oxygen. T/sub c/ shifts down to 65.4 K after treatment at 137 bars. The transitions remain sharp, with no evidence of significant structural change by x-ray powder diffraction. The original T/sub c/ is restored upon retreatment in O/sub 2/ at low partial pressure. The 110-K phase showed a much smaller shift (..delta..T/sub c/approx. =4 K) after treatment in O/sub 2/ at 134 bar.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Physics Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720
OSTI Identifier:
6407799
Resource Type:
Journal Article
Journal Name:
Phys. Rev. B: Condens. Matter; (United States)
Additional Journal Information:
Journal Volume: 39:10
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BISMUTH OXIDES; TRANSITION TEMPERATURE; CALCIUM OXIDES; COPPER OXIDES; STRONTIUM OXIDES; ANNEALING; FERMI LEVEL; HIGH PRESSURE; LOW PRESSURE; LOW TEMPERATURE; MEDIUM PRESSURE; PEROVSKITES; PRESSURE DEPENDENCE; QUANTITY RATIO; STOICHIOMETRY; SUPERCONDUCTIVITY; TEMPERATURE DEPENDENCE; VERY LOW TEMPERATURE; ALKALINE EARTH METAL COMPOUNDS; BISMUTH COMPOUNDS; CALCIUM COMPOUNDS; CHALCOGENIDES; COPPER COMPOUNDS; ELECTRIC CONDUCTIVITY; ELECTRICAL PROPERTIES; ENERGY LEVELS; HEAT TREATMENTS; OXIDES; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; STRONTIUM COMPOUNDS; THERMODYNAMIC PROPERTIES; TRANSITION ELEMENT COMPOUNDS; 360204* - Ceramics, Cermets, & Refractories- Physical Properties; 656100 - Condensed Matter Physics- Superconductivity

Citation Formats

Morris, D E, Hultgren, C T, Markelz, A M, Wei, J Y.T., Asmar, N G, and Nickel, J H. Oxygen concentration effect on T/sub c/ of the Bi-Ca-Sr-Cu-O superconductor. United States: N. p., 1989. Web. doi:10.1103/PhysRevB.39.6612.
Morris, D E, Hultgren, C T, Markelz, A M, Wei, J Y.T., Asmar, N G, & Nickel, J H. Oxygen concentration effect on T/sub c/ of the Bi-Ca-Sr-Cu-O superconductor. United States. https://doi.org/10.1103/PhysRevB.39.6612
Morris, D E, Hultgren, C T, Markelz, A M, Wei, J Y.T., Asmar, N G, and Nickel, J H. Sat . "Oxygen concentration effect on T/sub c/ of the Bi-Ca-Sr-Cu-O superconductor". United States. https://doi.org/10.1103/PhysRevB.39.6612.
@article{osti_6407799,
title = {Oxygen concentration effect on T/sub c/ of the Bi-Ca-Sr-Cu-O superconductor},
author = {Morris, D E and Hultgren, C T and Markelz, A M and Wei, J Y.T. and Asmar, N G and Nickel, J H},
abstractNote = {The T/sub c/ of Bi/sub 2/-Ca-Sr/sub 2/-Cu/sub 2/-O/sub 8-//sub x/ can be shifted reversibly over a rangel of at least 15 K by changing the oxygen concentration. T/sub c/ shifts downward for increased oxygen content. This is opposite to the shift seen in YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ and may be caused by reduction in the Fermi level reducing conductivity in the Bi-O layers. Oxygen concentration is varied by treatment in O/sub 2/ at appropriate pressures. The highest T/sub c/ = 78.5 K of the ''80-K'' phase is obtained by treating at 600 /sup 0/C in 10/sup -2/-bar oxygen. T/sub c/ shifts down to 65.4 K after treatment at 137 bars. The transitions remain sharp, with no evidence of significant structural change by x-ray powder diffraction. The original T/sub c/ is restored upon retreatment in O/sub 2/ at low partial pressure. The 110-K phase showed a much smaller shift (..delta..T/sub c/approx. =4 K) after treatment in O/sub 2/ at 134 bar.},
doi = {10.1103/PhysRevB.39.6612},
url = {https://www.osti.gov/biblio/6407799}, journal = {Phys. Rev. B: Condens. Matter; (United States)},
number = ,
volume = 39:10,
place = {United States},
year = {1989},
month = {4}
}