Continuous control of the superconducting transition temperature from overdoped to underdoped regimes in tetragonal Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}} thin films
- Department of Chemistry and New York State Institute on Superconductivity, Materials Synthesis Laboratory, State University of New York, Buffalo, New York 14260-3000 (United States)
- Materials Science Division and Science Technology Center for Superconductivity, Argonne National Laboratory, Argonne, Illinois 60439-4845 (United States)
Epitaxial superconducting thin films Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}} (Tl-2201) with a continuous range of doping levels have been synthesized. The films were made by rf magnetron sputtering and two-step postdeposition annealing, and their doping levels were controlled by varying the oxygen content through annealing in flowing argon. By annealing in flowing argon, the as-grown Tl-2201 thin films were changed continuously from the initially overdoped state, through the optimally doped state and then to the underdoped state. The normal state resistivity versus temperature curves of all the underdoped Tl-2201 thin films are convex, whereas those of the overdoped Tl-2201 thin films are all concave. Transmission electron microscopy bright-field images and selected area diffraction patterns of the 58 K underdoped Tl-2201 thin film showed neither twinning bands nor spot splitting associated with an orthorhombic crystal lattice. Therefore, it is concluded that underdoped Tl-2201 thin films are also tetragonal just like all the overdoped and optimally doped Tl-2201 thin films. {copyright} {ital 1997 American Institute of Physics.}
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 542514
- Journal Information:
- Applied Physics Letters, Vol. 71, Issue 12; Other Information: PBD: Sep 1997
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
THALLIUM OXIDES
TRANSITION TEMPERATURE
BARIUM OXIDES
COPPER OXIDES
SUPERCONDUCTING FILMS
THALLIUM COMPOUNDS
BARIUM COMPOUNDS
ELECTRIC CONDUCTIVITY
TRANSMISSION ELECTRON MICROSCOPY
DIFFUSION
HIGH-TC SUPERCONDUCTORS
DOPED MATERIALS
ANNEALING
STRUCTURAL CHEMICAL ANALYSIS
PHASE DIAGRAMS