Münster 1999 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 21: Postersitzung III: Hochfrequenzeigenschaften (1-4), Amorphe Systeme (5-9), Borkarbide (10-18), Quantenflüssigkeiten (19-25), Dünne Filme (26-49), Vortexdynamik, Pinning (50-63), M-I-Überg
änge, quantenkritische Ph
änomene (64-89)

TT 21.3: Poster

Donnerstag, 25. März 1999, 14:30–18:00, Foy

Multi-mode measurements in a dielectric resonator and studies on surface resistance of sintered YBa₂Cu₃O_7−δ — •A. Dierlamm, E. Keskin, R. Heidinger, and J. Halbritter — Forschungszentrum Karlsruhe, IMF, Postfach 3640, 76021 Karlsruhe

Commercially available YBCO powder was used to produce stoichiometric bulk material, where the sintering parameter were altered systematically. The oxygen concentration was determined by XRD measuring the c-axis lattice constant.

For a first characterization the surface resistance was measured in a copper endplate resonator using TE₀₁₁- and TE₀₁₂-modes at RT. Temperature dependent measurements were obtained in a niobium resonator of same shape.

Following MAFIA field computations, we built as an alternative a dielectric resonator system, which allows multi-mode measurements in a temperature range from 77K to RT and frequency range from 8GHz to 13GHz.

Measurement results are discussed in relation to the ansatz of the dc-resistance’s percolative description ρ(T)=∑ρ_K + p(ρ_0Lⁱ + αⁱ T).