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Bulk Superconductivity up to 122 K in the Tl-Pb-Sr-Ca-Cu-O System
Science (New York, N.Y.)
|October 14, 1988
Summary
New thallium-copper oxide superconductors, excluding barium, have been synthesized. These novel materials exhibit high critical temperatures (T(c)) up to 120 K, offering potential for advanced superconducting applications.
Area of Science:
- Materials Science
- Solid State Physics
- Inorganic Chemistry
Background:
- Development of high-temperature superconductors is crucial for energy and technology.
- Oxide superconductors, particularly those involving copper, have shown significant promise.
- Previous research focused on barium-containing cuprates, necessitating exploration of alternative compositions.
Purpose of the Study:
- To synthesize and characterize novel high-temperature superconductors.
- To investigate thallium-copper oxides not containing barium.
- To determine the superconducting properties, specifically the critical temperature (T(c)), of these new materials.
Main Methods:
- Solid-state synthesis techniques were employed to prepare the oxide materials.
- X-ray diffraction (XRD) was used for structural analysis and phase identification.
- Electrical resistivity measurements were conducted to determine the superconducting transition temperature (T(c)).
Main Results:
- New superconducting materials based on thallium and copper oxides, free of barium, were successfully prepared.
- The compound (Tl(0.5)Pb(0.5))Sr(2)CaCu(2)O(7) exhibited a T(c) of approximately 85 K.
- The compound (Tl(0.5)Pb(0.5))Sr(2)Ca(2)Cu(3)O(9) demonstrated a T(c) of approximately 120 K.
- Both materials crystallized in a tetragonal structure with specific lattice parameters determined by XRD.
- Single-crystal X-ray diffraction data allowed for a detailed structure refinement of the higher T(c) phase.
Conclusions:
- The successful synthesis of barium-free thallium-copper oxide superconductors expands the family of known high-T(c) materials.
- The achievement of T(c) values up to 120 K in these novel compounds highlights their potential for practical applications.
- The structural characterization provides fundamental insights into the relationship between composition, structure, and superconductivity in these systems.
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