Capacitive Properties of$rm YBa_2rm Cu_3rm O_7$ Grain Boundary Josephson Junctions Fabricated on 45$^circ$ [100] Tilt Asymmetric and 24$^circ$ [001] Tilt Symmetric Bicrystals
| Autor: | Luis L. Sánchez-Soto, F. Sánchez-Quesada, Ettore Sarnelli, M. L. Lucía, M.A. Navacerrada, G. Testa |
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| Rok vydání: | 2005 |
| Předmět: |
Permittivity
Josephson effect Materials science High-temperature superconductivity Condensed matter physics Relative permittivity Condensed Matter Physics Capacitance Electronic Optical and Magnetic Materials law.invention Tunnel effect Hysteresis law Grain boundary Electrical and Electronic Engineering |
| Zdroj: | IEEE Transactions on Appiled Superconductivity. 15:169-172 |
| ISSN: | 1051-8223 |
| DOI: | 10.1109/tasc.2005.849736 |
| Popis: | We present a comparative study of the electromagnetic parameters, mainly focused in the analysis of the capacitance (C) associated to the barrier, of YBa/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO) grain boundary Josephson junctions (GBJJs) fabricated on 24/spl deg/ [001] symmetric and 45/spl deg/ [100] asymmetric tilt bicrystalline substrates. The Swihart velocity (c~) is slightly affected by the nature of the barrier and mainly fixed by the junction width. However, a notable influence of the barrier structure, so of the geometry of the bicrystal substrate, on the relative dielectric constant to the barrier thickness ratio (/spl epsiv//sub r//t) values, so on C, has been found. We have observed that the capacitance values deduced by means of Fiske steps in YBCO 24/spl deg/ [001] symmetric and 45/spl deg/ [100] asymmetric GBJJs scale with junction resistance in opposite direction. This result could reveal the presence of a tunnel barrier in the YBCO 45/spl deg/ [100] asymmetric GBJJs. On the other hand, different capacitance values have been obtained by means of Fiske steps and hysteresis observed in the current-voltage characteristics in 45/spl deg/ [100] asymmetric GBJJs. An interpretation of this result can be made taking into account the contribution of the depleted YBCO layers close to the crystallographic grain boundary. |
| Databáze: | OpenAIRE |
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