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

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 convenie...

Full description

Saved in:
Bibliographic Details
Main Authors: Alford, N.M., Button, T.W., Peterson, G.E., Smith, P.A., Davis, L.E., Penn, S.J., Lancaster, M.J., Wu, Z., Gallop, J.C.
Format: Conference Proceeding
Language:English
Subjects:
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
CRYSTAL STRUCTURE
CRYSTALLOGRAPHY
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
GRAIN BOUNDARIES
GRAIN SIZE
HIGH-TC SUPERCONDUCTORS
MATERIALS SCIENCE
MICROSTRUCTURE
MICROWAVE EQUIPMENT
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
PHYSICAL PROPERTIES
RF SYSTEMS
SIZE
SUPERCONDUCTORS
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS 360204 > Ceramics, Cermets, & Refractories-- Physical Properties
YTTRIUM OXIDES
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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.
ISSN:0018-9464
1941-0069