Laser deposition of superconducting thin films
Laser deposition of Bi{sub 2}Sr{sub 2}Ca{sub n}Cu{sub n+1}O{sub y} (n = 0,1,2,3) superconducting thin films was performed. The effects of processing parameters on the film properties, including the target composition, oxygen pressure, and substrate temperature, have been studied. Unique relationships between the phase of the films with both the oxygen pressure and substrate temperature are shown. It has also become possible to fabricate nearly pure Bi{sub 2}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub y} and Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} films in the in-situ state by controlling these parameters. Best critical temperatures of 76 K and 100 K have been achieved for the in-situ Bi{sub 2}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub y} film and the annealed Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} film, respectively. Further investigation of the effect of the oxygen pressure on the Bi{sub 2}Sr{sub 2}Ca{sub n}Cu{sub n+1}O{sub y} (n = 1,2) films has been carried out. It is observed that even though the phases are the same, films show quite different properties depending on the oxygen pressure during film growth. In-situ films deposited at higher oxygen pressure show higher critical temperatures and critical current densities. However, by post annealing, transport properties of films deposited at low oxygen pressure are improved significantly. With respect to this difference, the results of x-ray diffraction and energy dispersive x-ray spectroscopy studies, and Hall effect measurements are discussed. The effect of metal doping on the properties of Bi{sub 2-x}Pb{sub x}Sr{sub 2}Ca{sub n}Cu{sub n+1}O{sub y} (n = 1,2) films with different Pb dopant concentrations (x) has been studied to explore defect structures in the films and film properties. The pinning potential and critical current density, measured from the resistive and magnetic hysteresis measurements, are found increased as the dopant concentration is increased.
- Research Organization:
- State Univ. of New York, Buffalo, NY (United States)
- OSTI ID:
- 39367
- Resource Relation:
- Other Information: TH: Thesis (Ph.D.); PBD: 1993
- Country of Publication:
- United States
- Language:
- English
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