Flux pinning in YBa sub 2 Cu sub 3 O sub 7 minus. delta. single crystals: Neutron irradiation and annealing

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.6441· OSTI ID:7266496

Vlcek, B M; Frischherz, M C; Fleshler, S; Welp, U; Liu, J Z; Downey, J; Vandervoort, K G; Crabtree, G W; Kirk, M A ^[1]; Giapintzakis, J ^[2]; Farmer, J ^[3]

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1. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
2. Material Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)
3. Missouri University Research Reactor, Columbia, Missouri 65211 (United States)

Results of dc magnetization on neutron ({ital n}) -irradiated YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} single crystals are presented. The crystals were irradiated to a fluence of 2{times}10{sup 17} {ital n}/cm{sup 2} ({ital E}{gt}0.1 MeV). The magnetization has been measured at 10, 40, and 70 K for both field orientations. The magnetization is thereby obtained by cooling the sample in zero field to the desired temperature. Then the field is ramped in steps of 0.25 T up to 5 T and reversed in the same steps. At each field the magnetization is measured. The hysteresis {Delta}{ital M} is defined as the difference in magnetization between descending and ascending branches in the hysteresis loop. At 10 K, we observe an increase of the hysteresis by a factor of 3 for {bold H}{parallel}{ital c} and by a factor of 10 for {bold H}{parallel}{ital a},{ital b} due to {ital n} irradiation. After irradiation, some of the crystals were annealed at 100, 200, and 300 {degree}C for 8 h each. After each annealing step, the critical current densities and the transition temperatures were determined again. We observe that following the 300 {degree}C annealing, the magnetization hysteresis for {bold H}{parallel}{ital a},{ital b} is almost reduced to the preirradiation level (a reduction in {ital J}{sub {ital c}} of 90%), in contrast to the {bold H}{parallel}{ital c} case, in which the decrease in hysteresis due to annealing is much less (a reduction in {ital J}{sub {ital c}} of 30%). Crystals irradiated under the same conditions were used for transmission-electron-microscopy (TEM) studies. By comparison between TEM and magnetization measurements, the role of the cascade defects in pinning was determined. It is furthermore shown by TEM that the cascade defects do not anneal for comparable annealing temperatures.

• DOE Contract Number: W-31109-ENG-38; FG02-90ER45427
• OSTI ID: 7266496
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 46:10; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
ANNEALING
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
HEAT TREATMENTS
HIGH-TC SUPERCONDUCTORS
MAGNETIC FLUX
MAGNETIZATION
MONOCRYSTALS
NEUTRON PROBES
OXIDES
OXYGEN COMPOUNDS
PROBES
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES