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Preparation and properties of the mercury based thin films of very High Tc superconductors and their possible applications in cryoelectronics

Abstract : The Hg-based superconductors are materials with the highest critical temperatures from all known superconductors. Their application as the devices for the everyday use is, however, limited due to the difficulties in their fabrication. The optimization of the preparation methods will open large possibilities for the cryoelectronic applications.
Within the frame of my dissertation thesis we tried to optimize the parameters of the synthesis of the thin Hg-based films. The development of the non-contact method for the mercuration of the thin films confirmed the film formation via Hg vapour phase which will enable the development of the devices for the mercuration of the larger samples (few cm). The lift-off method used for the patterning of the precursor films prevents the water contamination of the films and thus their degradation. The non-contact mercuration also enabled the fabrication of the Hg-based superconducting structures with the minimal risk of the short-circuits between the single parts of the structure. The formation of the Hg-1223 decreased the amount of the impurities on the top of the films which will enable the fabrication of the sandwich planar Josephson junctions, too.
The prepared coplanar structures are suitable for the use in the ultra-fast detectors. The structures containing microbridges can serve for the study of the superconductivity in the micro- and submicro- scale and for the fabrication of the Josephson junctions of such dimensions. The model structure of the superconducting fault-current limiter was the first step for the fabrication of the real limiter structure and will be used for the study of the superconducting properties on this type of the structure. The use of the sapphire substrate allows the application of the Hg-based superconducting structures also for the microwave devices.
All the structures had high values of the critical temperatures (up to 110 K for the coplanar strips and microbridges, up to 120 K for the limiter model structures) which provide the stability of the superconducting properties and parameters (coherent length, energy gap, etc.) at the working temperature of the superconductor (77 K).
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Contributor : Valerianova Michaela <>
Submitted on : Thursday, April 24, 2008 - 1:50:27 PM
Last modification on : Friday, December 18, 2020 - 1:08:04 PM
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Valerianova Michaela. Preparation and properties of the mercury based thin films of very High Tc superconductors and their possible applications in cryoelectronics. Material chemistry. Université Joseph-Fourier - Grenoble I, 2007. English. ⟨tel-00275549⟩

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