Abstract

Low-field microwave absorption in polycrystalline YBa₂Cu₃O₇₋ₓ was measured as a function of dc current applied through the sample at various temperatures below Tc. The peak-to-peak value of the magnetically modulated microwave absorption (MMMA) signal increases with dc current at a fixed temperature. Above a threshold value of the current, the absorption signal level rapidly drops to zero, indicating quenching of superconductivity. If this critical current is plotted as a function of temperature, the results can be explained on the basis of the flux creep model. The MMMA signal obeys a scaling rule as predicted by the flux creep model. We conclude that flux creep limits the critical current density in these materials; also, this presents a new way of measuring critical current densities while using only a two-contact method. It gives some insight into the relationship between microwave properties and dc transport phenomena in these superconductors.

Notes

Originally published in Journal of Applied Physics 67, 5076 (1990). DOI:10.1063/1.344675 (http://dx.doi.org/10.1063/1.344675).

Keywords

magnetically modulated microwave absorption, dc transport current, polycrystalline YBCO, YBa₂Cu₃O₇₋ₓ, MMMA, absorption signal level, flux creep model

Subject Categories

Superconductors, Superconductivity

Disciplines

Electromagnetics and photonics

Publisher

American Institute of Physics

Publication Date

5-1-1990

Rights Information

Copyright 1990 American Institute of Physics.

Rights Holder

American Institute of Physics

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