Superconductivity in Y{sub 0.6}Pr{sub 0.4}Ba{sub 2{minus}{ital x}}Sr{sub {ital x}}Cu{sub 3}O{sub 7{minus}{delta}}: The role of apical oxygen in hybridization
- Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)
- Department of Physics, Beijing Normal University, Beijing 100875 (China)
- National Laboratory for Superconductivity, Beijing 100080 (China)
The structural and electric properties of Y{sub 0.6}Pr{sub 0.4}Ba{sub 2{minus}{ital x}}Sr{sub {ital x}}Cu{sub 3}O{sub 7{minus}{delta}} have been investigated as a function of {ital x}. X-ray powder-diffraction patterns indicate that a solid solution forms with {ital x} extending to about 1.4. It is found that the substitution of Sr for Ba results in a contraction in the {ital c} axis at the same rate as in YBa{sub 2{minus}{ital x}}Sr{sub {ital x}}Cu{sub 3}O{sub 7{minus}{delta}}. The oxygen content and {ital T}{sub {ital c}} are found to remain essentially unchanged with increasing Sr. Our analysis suggests that the contraction in {ital c} arises mainly from the shift of the apical oxygen and from a shift of Ba(Sr) towards the CuO{sub 2} planes. The apparent shift of the apical oxygen does not seem to influence the hybridization between the Pr 4{ital f} electrons and the valence band of the CuO{sub 2} planes significantly. The hybridization is more sensitive to the bond length between the Pr and the oxygen located in the CuO{sub 2} planes. {ital T}{sub {ital c}} in this system appears to be controlled both by the shift of the apical oxygen and by the hybridization.
- OSTI ID:
- 55097
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 51, Issue 22; Other Information: PBD: 1 Jun 1995
- Country of Publication:
- United States
- Language:
- English
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