Pressure dependence of the superconducting critical temperature of Tl{sub 2}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+{ital y}} and Tl{sub 2}Ba{sub 2}Ca{sub 3}Cu{sub 4}O{sub 12+{ital y}} up to 21 GPa
- Department of Physics and Astronomy, Free University, De Boelelaan 1081, 1081 HV Amsterdam (The Netherlands)
- Institute for Industrial Research & Development, Gracefield Research Centre, Gracefield Road, P.O. Box 31310, Lower Hutt (New Zealand)
- Department of Chemistry, National Taiwan University, Roosevelt Road, Section 4, Taipei, Taiwan, Republic of (China)
Using a cryogenic diamond anvil cell (DAC) the pressure dependence of the superconducting transition temperature {ital T}{sub {ital c}} of Tl{sub 2}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+{ital y}} (Tl-2223) and Tl{sub 2}Ba{sub 2}Ca{sub 3}Cu{sub 4}O{sub 12+{ital y}} (Tl-2234) has been measured resistively up to 21 GPa. At ambient pressure these compounds have {ital T}{sub {ital c}}{close_quote}s of 128.5 K and 113 K. At low pressures, the pressure dependence {partial_derivative}{ital T}{sub {ital c}}/{partial_derivative}{ital p} is 1.75 K/GPa in Tl-2223 and 2.0 K/GPa in Tl-2234. As pressure is increased {ital T}{sub {ital c}} continues to increase (although the rate diminishes) until {ital T}{sub {ital c}} reaches a maximum of 133 K at 4.2 GPa in Tl-2223 and of 120 K at 6.6 GPa in Tl-2234. At higher pressures {ital T}{sub {ital c}} decreases. In this region a rather abrupt change in {partial_derivative}{ital T}{sub {ital c}}/{partial_derivative}{ital p} is observed at {ital p}{sub {ital c}}=12.0 GPa in Tl-2223 and at {ital p}{sub {ital c}}=10.5 GPa in Tl-2234. The kink at {ital p}{sub {ital c}} is interpreted as an indication of the presence of {ital inequivalent} CuO{sub 2} layers: Below {ital p}{sub {ital c}} the {ital T}{sub {ital c}} of the samples is determined by the intrinsic {ital T}{sub {ital c}} of the outer CuO{sub 2} layers while above {ital p}{sub {ital c}} it is determined by that of the inner CuO{sub 2} layers. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 385710
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 54, Issue 14; Other Information: PBD: Oct 1996
- Country of Publication:
- United States
- Language:
- English
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