Low frequency voltage noise in high temperature superconductor josephson junctions

A. Marx, L. Alff, R. Gross

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

We have performed detailed measurements of 1/f voltage noise in a variety of bicrystal grain boundary Josephson junctions and in ramp edge junctions with artificial barriers. Fluctuations of the junction critical current Ic and the normal state resistance Rn were found to fully account for the measured 1/f noise. For the normalized fluctuations Sr and SR which were found to be independent of temperature a linear scaling with Rn has been observed. Correlation experiments proved that the fluctuations of Ic and Rn are anti-phase correlated. The ratio ST/SR of the normalized fluctuations is in close agreement with the scaling of the IcRn-product indicating a common underlying physical mechanism. Our analysis strongly supports the Intrinsically Shunted Junction (ISJ) model based on an insulating grain boundary containing a high density of localized defect states with fluctuating electron occupation causing 1/f noise. The effective charge trapping time within single traps shows thermally activated behavior and was found to decay exponentially with increasing bias voltage.

Original languageEnglish
Pages (from-to)2719-2722
Number of pages4
JournalIEEE Transactions on Applied Superconductivity
Volume7
Issue number2 PART 3
DOIs
StatePublished - 1997
Externally publishedYes

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