The behavior of thermopower in the YBa2−x
LaxCu3Oy system. Correlation between the band parameters in normal state and critical temperature |
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Authors: | V É Gasumyants E V Vladimirskaya I B Patrina |
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Institution: | (1) St. Petersburg State Technical University, 195251 St. Petersburg, Russia;(2) Institute of Silicate Chemistry, Russian Academy of Sciences, 195155 St. Petersburg, Russia |
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Abstract: | The thermopower in the YBa2−x
LaxCu3Oy system (x=0–0.5) has been studied. An analysis made in terms of the narrow-band model revealed trends in the variation of the main
band parameters with increasing lanthanum concentration. The dependence of the conduction band width on lanthanum concentration
was found to pass through a weak minimum at x=0.05–0.1, which correlates in position with the maximum in the concentration dependences of the critical temperature and
degree of sample orthorhombicity. The results obtained and their comparison with Fe, Co→Cu substitution data permit a conclusion
that the main factor affecting the properties of the YBa2Cu3Oy system under nonisovalent substitution of various cations is the increasing disorder in the chain-oxygen subsystem caused
by increasing impurity content.
Fiz. Tverd. Tela (St. Petersburg) 40, 17–22 (January 1998) |
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Keywords: | |
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