title: Anomalous pressure dependence of the superconducting transition temperature of beta-pyrochlore AOs2O6 oxides.
abstract: High-pressure effects on the superconducting transitions of beta-pyrochlore oxide superconductors AOs(2)O(6) (A = Cs,Rb,K) are studied by measuring resistivity under high pressures up to 10 GPa. The superconducting transition temperature T(c) first increases with increasing pressure in every compound and then exhibits a broad maximum at 7.6 K (6 GPa), 8.2 K (2 GPa), and 10 K (0.6 GPa) for A = Cs, Rb, and K, respectively. Finally, the superconductivity is suppressed completely at a critical pressure near 7 GPa and 6 GPa for A = Rb and K and probably above 10 GPa for A = Cs. Characteristic changes in the coefficient A of the T(2) term in resistivity and residual resistivity are observed, both of which are synchronized with the corresponding change in T(c).
authors.affiliation: Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Muramatsu
authors.forename: N
authors.initials: N
authors.lastname: Takeshita
authors.forename: C
authors.initials: C
authors.lastname: Terakura
authors.forename: H
authors.initials: H
authors.lastname: Takagi
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura
authors.forename: S
authors.initials: S
authors.lastname: Yonezawa
authors.forename: Y
authors.initials: Y
authors.lastname: Muraoka
authors.forename: Z
authors.initials: Z
authors.lastname: Hiroi