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Enhancement of the noise spectral densities near the resistive transition region of YBCO micro-bridge
- Source :
- Solid State Communications. 81:269-273
- Publication Year :
- 1992
- Publisher :
- Elsevier BV, 1992.
-
Abstract
- We have systematically measured the noise power spectral density ( S υ ( f )) of the YBCO micro-bridge as a function of frequency, temperature and magnetic field. In all the cases above, S υ ( f ) shows V 2 / f α behaviour at the measured frequency range of 0.2 f V , the d.c. voltage across the sample and, α the fitting parameter to be determined. In the normal state, the normalized noise power spectral density ( S n ( f ) = S υ ( f )/ V 2 ) is four or five orders of magnitude larger than that of the normal metals evaluated by Hooge's formula or thermal fluctuation model. Near the zero resistance temperature ( T c 0 , S n ( f ) was found to further increase by eight orders of magnitude and α was shown to increase from 1 to 2 depending on the frequency range. Furthermore, once a magnetic field is applied, S n ( f ) showed a marked increase near T c O . This anomaly is attributed to magnetoic vortices coupled with the enhanced instability of space-time coherence associated with Cooper pair as a result of applied magnetic field.
- Subjects :
- chemistry.chemical_classification
High-temperature superconductivity
Condensed matter physics
Chemistry
Spectral density
General Chemistry
Condensed Matter Physics
Noise (electronics)
law.invention
Magnetic field
law
Materials Chemistry
Coherence (signal processing)
Orders of magnitude (speed)
Cooper pair
Inorganic compound
Subjects
Details
- ISSN :
- 00381098
- Volume :
- 81
- Database :
- OpenAIRE
- Journal :
- Solid State Communications
- Accession number :
- edsair.doi...........53ba061a9cd36ca76a0d368cb43721a1