Abstract
We report measurements and modeling of microwave-frequency vortex dynamics in YBCO grain boundaries that are modeled as long Josephson junctions by numerically solving the sine-Gordon equation. YBCO bicrystal grain boundaries with misorientation angles from 2 to 24° have been studied experimentally using microwave resonator measurement techniques. Comparison between the measured and calculated microwave impedance and the harmonic generation of the 24° grain boundaries indicates that the 24° grain boundaries are weakly coupled long Josephson junctions. The corresponding results of lower angle grain boundaries are also presented. A transition from strong-coupled single-crystal-like behavior to weak-coupled Josephson-junction-like behavior has been observed in a 10° grain boundary between 55 and 75 K. The physics of Josephson-vortex dynamics and its impact on the microwave properties of superconducting thin films are discussed.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 637-649 |
| Number of pages | 13 |
| Journal | Journal of Superconductivity |
| Volume | 14 |
| Issue number | 5 |
| State | Published - 2001 |
| Externally published | Yes |
Keywords
- Grain boundaries
- Microwave properties
- Surface resistance
- Vortex dynamics
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Physics and Astronomy (miscellaneous)