Thin-film high-Tc superconductors (bibtex)

by Wolfgang Volz

Abstract:

The magnetoresistance of YBa_{2}Cu_{3}O_{7-x} - PrBa_{2}Cu_{3}O_{7-x} (YBCO-PrBCO) superlattices is studied in the vicinity of the transition temperature in magnetic fields perpendicular to the a-b plane up to 5.5 Tesla. For the 7YBCOx7PrBCO and the 7YBCOx14PrBCO superlattice we get an excellent fitting according to the Larkin 2-D superconducting fluctuation theory. We relate this behavior to a complete interlayer decoupling between the YBCO layers. Because of the equal thickness of the YBCO layers for both samples, we obtained for the fluctuation amplitude, the fluctuating sheet resistance and the critical temperature of the quasi two-dimensional superconducting layer almost the same results for both superlattices. One of the two fit parameters, H_{phi}(T), is consistent for both samples with the theoretical prediction of Reizer for the quasi two dimensional electron-electron interaction. Additionally, we found that the resistivities for rho -> rho_{0} are not caused directly by fluctuations, but rather is related to thermally assisted flux creep.

Reference:

Wolfgang Volz, "Thin-film high-Tc superconductors", 1994.

Bibtex Entry:

@bachelorsthesis{1994V, title={Thin-film high-Tc superconductors}, author={Wolfgang Volz}, month={February}, year={1994}, abstract={The magnetoresistance of YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub> - PrBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub> (YBCO-PrBCO) superlattices is studied in the vicinity of the transition temperature in magnetic fields perpendicular to the a-b plane up to 5.5 Tesla. For the 7YBCOx7PrBCO and the 7YBCOx14PrBCO superlattice we get an excellent fitting according to the Larkin 2-D superconducting fluctuation theory. We relate this behavior to a complete interlayer decoupling between the YBCO layers. Because of the equal thickness of the YBCO layers for both samples, we obtained for the fluctuation amplitude, the fluctuating sheet resistance and the critical temperature of the quasi two-dimensional superconducting layer almost the same results for both superlattices. One of the two fit parameters, H<sub>phi</sub>(T), is consistent for both samples with the theoretical prediction of Reizer for the quasi two dimensional electron-electron interaction. Additionally, we found that the resistivities for rho -> rho<sub>0</sub> are not caused directly by fluctuations, but rather is related to thermally assisted flux creep.}, note={Supervised by F.S. Razavi} }

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