Surface resistance and penetration depth anomalies near the superconducting transition in YBCO thick films at low frequencies
✍ Scribed by A.C. Bódi; T. Kokkomäki; S. Leppävuori; J. Väyrynen
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 425 KB
- Volume
- 253
- Category
- Article
- ISSN
- 0921-4534
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✦ Synopsis
During the normal-superconductor transition, surface resistance and penetration depth peak anomalies have been observed in YBCO thick films on Zr(Y)O 2 substrates, between 1 kHz and 1 MHz frequencies. The resonance curve-like anomaly's amplitude depends linearly upon the frequency and not on the thickness of the film. It is not connected directly to the film's intrinsic superconductivity properties, such as T c and Je, and is not sensitive to the direction of the temperature sweep. The penetration depth presents a A ctf -l frequency dependence. The frequency dependence of the AC flux penetration's onset temperature is in agreement with that predicted by the vortex-glass model. We believe the anomaly could arise from the competition between the temperature dependence of the critical current density and that of the mixed state's volume.