Detailed studies on the properties of low frequency noise in Y-Ba-Cu-O thin films in the transition region were conducted. Our experimental results showed that the low frequency excess noise exhibited a lower cutoff frequency of about 5 Hz, below which the noise power spectra were independent of frequency. At T close to Tc and at small current biases the voltage noise power spectra were proportional to 12, and inversely proportional to the volume of the device, Ω. In addition, low frequency noise measured from two segments separated by a distance of 300 µm was found to be correlated. The lower cutoff frequencies computed for both the noise power spectra and the frequency dependent correlation function, according to the thermal fluctuation model, were found to be in good agreement with the experimental values. The experimental results provide strong evidence that the low frequency excess noise in the device originates from equilibrium temperature fluctuations for small I and T ~ Tc.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering