Power-dependent microwave properties of superconductingYBa2Cu3O7−xfilms on buffered polycrystalline substrates
作者:
A. T. Findikoglu,
P. N. Arendt,
S. R. Foltyn,
J. R. Groves,
Q. X. Jia,
E. J. Peterson,
L. Bulaevskii,
M. P. Maley,
D. W. Reagor,
期刊:
Applied Physics Letters
(AIP Available online 1997)
卷期:
Volume 70,
issue 24
页码: 3293-3295
ISSN:0003-6951
年代: 1997
DOI:10.1063/1.118431
出版商: AIP
数据来源: AIP
摘要:
We have studied the microwave properties of 0.4 &mgr;m thickYBa2Cu3O7−x(YBCO) films on polycrystalline substrates with ion-beam-assisted-deposited yttria-stabilized zirconia buffer layers using a parallel-plate resonator technique at 10 GHz. The YBCO films with similar in-plane texture grown on both forsterite and Ni-based alloy substrates show similar microwave properties. We measure low-power surface resistanceRsvalues of about 0.5 m&OHgr; at 76 K and 0.15 m&OHgr; at 4 K for films with an in-plane mosaic spread of about 7°. Single-tone power-dependence measurements show that the surface resistance and the surface reactance increase linearly and by the same amount with increasing microwave field level. At intermediate power levels, the intermodulation measurements show odd-order intermodulation products that increase quadratically with two-tone input power. These results indicate a hysteretic vortex penetration mechanism in the weak links as the most plausible source of the observed nonlinearities in these films. ©1997 American Institute of Physics.
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