Nonlinear Meissner effect in a high-temperature superconductor: Local versus nonlocal electrodynamics

Measured intermodulation distortion (IMD) power at 1.5 GHz in a series of YBa[subscript 2]Y[subscript 3]O[subscript 7−δ] stripline resonators of varying strip widths is compared to the predictions of two qualitatively distinct theories of the nonlinear Meissner effect. The stripline resonators are patterned from a single wafer to ensure uniformity of the material properties. According to the first theory [T. Dahm and D. J. Scalapino, Phys. Rev. B 60, 13125 (1999)], the IMD power is dominated by contributions from the strip edges, while according to the second theory [D. Agassi and D. E. Oates, Phys. Rev. B 72, 014538 (2005)] it is dominated by contributions from the body of the strip. The parameter-free comparison of the measured data with the theoretical predictions clearly favors the latter theory. We conclude that the nonlinear component of the penetration depth must be treated with nonlocal electrodynamics. The origins of this outcome are discussed briefly in the framework of a Green’s-function approach

Hochtemperatur-Supraleiter-Systeme in der Satellitenkommunikation. Teilvorhaben: Grossflaechige YBCO-Filme mit gezielten HF-Eigenschaften bei 4 GHz Abschlussbericht

For applications of HTSC thin films in satellite communication systems we evaporated YBCO films on sapphire and LAO substrates and studied their behaviour. With the construction and development of different microwave measurement systems we were able to optimize their rf-properties. We characterized small and large sized samples by measuring the temperature and power dependent surface resistance. (orig.)SIGLEAvailable from TIB Hannover: DtF QN1(76,21) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman