Surface resistance of bulk and thick film YBa sub 2 Cu sub 3 O sub x

Conference · Fri Mar 01 04:00:00 EST 1991 · IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (United States)

OSTI ID:5620712

Alford, N M; Button, T W ^[1]; Peterson, G E ^[2]; Smith, P A; Davis, L E ^[3]; Penn, S J ^[4]; Lancaster, M J; Wu, Z ^[5]; Gallop, J C ^[6]

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1. ICI Advanced Materials, P.O. Box 11, The Heath, Runcorn, Cheshire WA7 4QE (GB)
2. AT and T Bell Labs., Murray Hill, NJ (United States)
3. Dept. of Electrical and Electronic Engineering, UMIST, Manchester M6O 1QD (GB)
4. Liverpool Univ. (United Kingdom). Dept. of Physics
5. Birmingham Univ. (United Kingdom)
6. National Physical Lab., Teddington (United Kingdom)

The surface resistance, R{sub s}, of high temperature oxide superconductors (HTS) varies as f{sup n}, where f is frequency and the exponent n varies generally between 1 and 2. The R{sub s} of copper varies approximately as f{sup 1/2}. The crossover frequency, fc, between copper and HTS is a convenient indicator of sample quality in radio- frequency and microwave applications, the goal being as high a crossover frequency as possible. The R{sub s} of YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) has been measured by a coaxial method i.e. a copper outer shield and a HTS central conductor and also by using an all-YBCO TE{sub 011} cavity. The microstructure of the ceramic has been deliberately altered so that variables such as starting powder size and phase purity, ceramic density, phase composition, grain size and number of grain boundaries may be evaluated. A number of experiments have been conducted so that the variables chosen might be studied independently. The results show that R{sub s} varies in a complex manner according to the microstructure and that as sintered grain size is reduced to a certain size that R{sub s} is reduced. Further decreases in grain size are associated with an increase in the R{sub s} suggesting that grain boundary detritus and grain boundaries themselves are sources of loss. In this paper examples are given to show that R{sub s} diminishes in c-axis oriented YBCO thick films.

• OSTI ID: 5620712
• Report Number(s): CONF-900944--
• Conference Information: Journal Name: IEEE Transactions on Magnetics (Institute of Electrical and Electronics Engineers); (United States) Journal Volume: 27:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
CRYSTAL STRUCTURE
CRYSTALLOGRAPHY
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
EQUIPMENT
GRAIN BOUNDARIES
GRAIN SIZE
HIGH-TC SUPERCONDUCTORS
MICROSTRUCTURE
MICROWAVE EQUIPMENT
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
PHYSICAL PROPERTIES
RF SYSTEMS
SIZE
SUPERCONDUCTORS
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES