Film thickness dependence of microwave surface resistance for YBa2Cu3O7thin films
| Autor: | A. Mogro‐Campero, D. S. Mallory, L. G. Turner, A. M. Kadin |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 73:5295-5297 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.353764 |
| Popis: | Microwave surface resistance close to 10 GHz has been measured as a function of temperature for epitaxial thin films of YBa2Cu3O7 (YBCO) on LaAlO3 in the film thickness range of 0.2–0.8 μm. The films were made by a reduced‐temperature post‐anneal technique. The surface resistance (Rs) scaled to 10 GHz decreases with increasing film thickness as is expected due to the finite film thickness with respect to the magnetic penetration depth. Below about 70 K there is an increase in Rs for the thickest films, attributed to a change in microstructure from c axis normal to the substrate plane, to c axis in the plane of the substrate; the resulting minimum in Rs occurs at a film thickness of 0.6 μm. The critical current density (Jc) at 77 K is highest for the thinner films, so that films with the highest Jc do not have the lowest measured Rs. These results suggest that the optimum YBCO film thickness for microwave devices patterned from these films may be about 0.6 μm, depending on operating temperature. |
| Databáze: | OpenAIRE |
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