Origins of conductive losses at microwave frequencies in YBa2Cu3O7??/LaAlO3/YBa2Cu3O7?? trilayers deposited by pulsed laser deposition
| Autor: | Douglas B. Chrisey, M. S. Osofsky, Kenneth S. Grabowski, James S. Horwitz, K.R. Carroll, Jeffrey M. Pond, H. S. Newman, C. M. Cotell |
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| Rok vydání: | 1994 |
| Předmět: |
Superconductivity
Materials science Physics and Astronomy (miscellaneous) business.industry Dielectric Condensed Matter Physics Electronic Optical and Magnetic Materials Pulsed laser deposition Surface conductivity Electrical resistivity and conductivity Optoelectronics Dissipation factor business Layer (electronics) Microwave |
| Zdroj: | Journal of Superconductivity. 7:965-969 |
| ISSN: | 1572-9605 0896-1107 |
| Popis: | Oriented YBa2Cu3O7−δ/LaAlO3/YBa2Cu3O7−δ trilayers were deposited by pulsed laser deposition (PLD) onto 〈100〉 MgO and LaAlO3. Film thicknesses varied from 2000–5000 A/ layer. A comparision of structure and transport data for the bottom and top superconducting layers indicated a slight decrease in film quality for the top superconducting layer. The critical temperature was lower for the top superconducting layer (90.5 vs. ∼90 K) and the microwave surface resistance was higher (increasing from ∼2 to 18 mω at 36 GHz, 20 K). The resistivity of the dielectric was estimated to be 106 ω cm, and the loss tangent of the dielectric film at microwave frequencies had an upper limit of 0.01. Cross-sectional TEM analysis of the trilayer structure showed a high density of threading dislocations in the dielectric layer that appeared to nucleate at steps in the underlying superconducting layer. The threading dislocations may serve as conduction paths in the LaAlO3 layer. |
| Databáze: | OpenAIRE |
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