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Author Sugawara, K. ♦ Baar, D. J. ♦ Murakami, M. ♦ Kondoh, A. ♦ Shiohara, Y. ♦ Tanaka, S. ♦ Yamaguchi, K.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ BARIUM COMPOUNDS ♦ MAGNETIC FLUX ♦ YTTRIUM COMPOUNDS ♦ ABSORPTION SPECTRA ♦ COATINGS ♦ CRITICAL CURRENT ♦ CUPRATES ♦ DPPH ♦ ELECTRON SPIN RESONANCE ♦ HIGH-TC SUPERCONDUCTORS ♦ LINE WIDTHS ♦ MELTING ♦ MICROWAVE SPECTRA ♦ POWDERS ♦ ALKALINE EARTH METAL COMPOUNDS ♦ COPPER COMPOUNDS ♦ CURRENTS ♦ ELECTRIC CURRENTS ♦ MAGNETIC RESONANCE ♦ NITRO COMPOUNDS ♦ ORGANIC COMPOUNDS ♦ ORGANIC NITROGEN COMPOUNDS ♦ OXYGEN COMPOUNDS ♦ PHASE TRANSFORMATIONS ♦ RADICALS ♦ RESONANCE ♦ SPECTRA ♦ SUPERCONDUCTORS ♦ TRANSITION ELEMENT COMPOUNDS ♦ Ceramics, Cermets, & Refractories- Superconducting Properties- (1992-) ♦ Ceramics, Cermets, & Refractories- Physical Properties ♦ Techniques of General Use in Physics- (1992-)
Abstract This paper reports that the electron spin resonances of both DPPH surface coatings and Y{sub 2}Ba{sub 1}Cu{sub 1}O{sub 5} (211 phase) non-superconducting inclusions have been used to probe the flux pinning in high critical current density Y-Ba-Cu-O bulk superconductors prepared by the MPMG (Melt-Powder-Melt-Growth) method. The ESR lineshapes for both the surface coatings and the 211 inclusions were observed to broaden when the MPMG samples entered the superconducting state. The excess ESR linewidth for the DPPH coatings was found to increase monotonically with decreasing temperature, as the result of increasing field gradients due to pinned flux. The ESR linewidth of the 211 inclusions had a complicated temperature dependence. This linewidth was less than that of isolated Y{sub 2}Ba{sub 1}Cu{sub 1}O{sub 5} below 20 K, possibly due to a lower magnetic ordering temperature, mechanical stress, and/or different composition of the inclusions as compared to isolated Y{sub 2}Ba{sub 1}Cu{sub 1}O{sub 5}. Strong hysteresis in the ESR linewidths due to flux trapping was observed at low temperatures. Comparisons with the ESR linewidth of DPPH coated on the surface of the samples suggest that this flux trapping is due to strong pinning in the neighborhood of the 211 inclusions.
ISSN 02179849
Educational Use Research
Learning Resource Type Article
Publisher Date 1991-06-01
Publisher Place United States
Journal Modern Physics Letters B
Volume Number 5
Issue Number 14


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