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Thermal Expansion and Superconductivity in Alkali Metal‐ and Silver‐doped BiSrCaCuO System
Author(s) -
Krishna B. Gopala,
Chandra G. Ravi,
Suryanarayana S. V.
Publication year - 1992
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170270426
Subject(s) - alkali metal , analytical chemistry (journal) , electrical resistivity and conductivity , thermal expansion , doping , superconductivity , alkaline earth metal , metal , materials science , phase (matter) , mineralogy , chemistry , metallurgy , condensed matter physics , physics , optoelectronics , organic chemistry , chromatography , quantum mechanics
Samples with the nominal composition Bi 2 Sr 2 CaCu 2 O y with na doped at the Ca site and K doped at the Sr site are prepared by solid state reaction method. From the X‐ray diffraction data it is found that all the the samples have exhibited a single phase 2212. The D.C. electrical resistivity data show that for Na‐doped samples the T c (zero) varies from 80 K to 85 K and for K‐doped samples it is from 79 K to 82 K. The loss of oxygen from these samples around 400°C was confirmed by high temperature dilatometry. The variation of the thermal expansion coefficient (“α”) with temperature for different alkali dopings are discussed. Also the samples with the nominal composition Bi 4 Sr 3 Ca 3 Cu 4− x Ag x O y (with x = 0, 0.1, 0.2, 0.3) were studied.