EFFECT OF GROWTH-INDUCED LINEAR DEFECTS ON HIGH FREQUENCY PROPERTIES OF PULSE-LASER DEPOSITED YBa2Cu3O7-d FILMS

Growth-induced linear defects affect the microwave surface resistance, Rs, of highly biaxially oriented high temperature superconductor (HTS) YBa2Cu3O7-d (YBCO) films. Measured Rs(77 K) turned out to be 4-5 times higher than in single crystals. The films were deposited by modified pulse-laser techni...

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Bibliographic Details
Published in:Journal of superconductivity 2001-01, Vol.14 (1), p.105-114
Main Authors: Pan, V M, Flis, V S, Karasevska, O P, Matsui, V I, Peshko, I I, Svetchnikov, V L
Format: Article
Language:English
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Summary:Growth-induced linear defects affect the microwave surface resistance, Rs, of highly biaxially oriented high temperature superconductor (HTS) YBa2Cu3O7-d (YBCO) films. Measured Rs(77 K) turned out to be 4-5 times higher than in single crystals. The films were deposited by modified pulse-laser technique, Jc (77 K) = (3-6) x 106 A/cm2, onto LaAlO3 substrates. Rs(T) was measured at 134 GHz and 20-100 K. TEM/HREM study of YBCO films deposited at Ts = 750 C-780 C revealed a reduction of edge dislocation density with Ts increase (from 2 x 1011 to 1010 lines/cm2). YBCO films deposited at Ts = 780 C exhibited the smallest Rs(77 K, 134 GHz) < 120 mOHM and the lowest density of dislocations detected by HREM and X-ray analysis. The nature of the dislocation effect is discussed within a model of local anisotropic elastic deformation in a vicinity of dislocation cores, where Tc variation and an enhancement of normal quasi-particle density are significant. 39 refs.
ISSN:0896-1107