Magnetic field-induced recovery of superconductivity in epitaxial YBa2Cu3O7-x films at microwave frequencies

被引：26

作者：

Hein, MA

Bauer, C

Diete, W

Hensen, S

Kaiser, T

Kresin, VZ

Muller, G

机构：

[1] Berg Univ Gesamthsch Wuppertal, FB Phys, D-42097 Wuppertal, Germany

[2] Accel Instruments GMBH, D-51429 Bergisch Gladbach, Germany

[3] Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA

来源：

JOURNAL OF SUPERCONDUCTIVITY | 1997年 / 10卷 / 05期

关键词：

surface impedance; penetration depth; high-temperature superconductors; pair breaking; two-fluid model;

D O I：

10.1007/BF02767683

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

An anomalous magnetic field-effect has been observed in the microwave surface impedance of epitaxial YBa2CU3O7-x films on LaAlO3 substrates. The application of de and microwave magnetic fields up to 20 mT caused a significant decrease of microwave surface reactance X-s (less than or equal to 3%) and resistance R-s (less than or equal to 20%) at 8.5 GHz, 77 K and at 87 GHz, 4.2 K. The field effects on X, and R, were found to correlate within the framework of the two-fluid model. The observed effect is attributed to the presence of magnetic impurities in the superconducting films, giving rise to pair breaking. Alignment of the impurity spins suppresses the spin-flip scattering rate and, as a result, leads to a recovery of microwave superconductivity.

引用

页码：485 / 493

页数：9

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