ac susceptibility in YBa[sub 2](Cu[sub 1[minus][ital x]]Fe[sub [ital x]])[sub 3]O[sub 7[minus][delta]]: Evidence for two-step irreversibility-line crossover

Journal Article · Thu Jul 01 00:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.483· OSTI ID:5529012

Mehbod, M ^[1]; Sergeenkov, S; Ausloos, M ^[2]; Schroeder, J ^[1]; Dang, A ^[3]

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1. Service de Physique des Solides, Universite Libre de Bruxelles, CP 233, boulevard du Triomphe, B-1050 Brussels (Belgium)
2. S.U.P.RS., B5, Institute of Physics, University of Liege, Sart Tilman, B-4000 Liege (Belgium)
3. S.U.P.RS., B5, Institute of Physics, University of Liege, Sart Tilman, B-4000 Liege (Belgium) Service de Physique des Solides, Universite Libre de Bruxelles, CP 233, boulevard du Triomphe, B-1050 Brussels (Belgium)

The ac susceptibilities of YBa[sub 2](Cu[sub 1[minus][ital x]]Fe[sub [ital x]])[sub 3]O[sub 7[minus][delta]] polycrystals for 0[le][ital x][lt]0.05 have been measured as a function of temperature and magnetic-field strength. Two different types of behavior of the irreversibility line, [ital T][sub [ital m]]([ital H]), obeying the law 1[minus][ital T][sub [ital m]]/[ital T][sub [ital c]][similar to][ital H][sup [ital q]] have been found. One corresponds to pure Y-Ba-Cu-O ([ital x]=0) and shows the commonly observed change of the power exponent [ital q] from 2/3 to 1 with increasing field. For the iron-doped samples an additional unusual crossover from [ital q]=1 to [ital q]=4/3 is observed practically within the same field and temperature interval as for the undoped one. The obtained results are described via the critical-state model taking into account the modification of the Josephson medium for the iron-doped case. In contrast to the silver-doped case [S.L. Shinde [ital et] [ital al]., Phys. Rev. B 41, 8838 (1990)], the pinning-force densities turn out to be smaller for iron-doped Y-Ba-Cu-O as compared to the undoped sample, probably due to iron-induced creation of a weak-link network inside grains.

• OSTI ID: 5529012
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 48:1; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
MAGNETIC SUSCEPTIBILITY
COPPER OXIDES
HIGH-TC SUPERCONDUCTORS
YTTRIUM OXIDES
GRAIN BOUNDARIES
IRON ADDITIONS
SUBSTOICHIOMETRY
TEMPERATURE DEPENDENCE
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
IRON ALLOYS
MAGNETIC PROPERTIES
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties