A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Pinning centres and enhancement of critical current density in YBCO doped with Pr, Ca and Ni
Tekijät: Huhtinen H, Awana VPS, Gupta A, Kishan H, Laiho R, Narlikar AV
Kustantaja: IOP PUBLISHING LTD
Julkaisuvuosi: 2007
Lehti:: Superconductor Science and Technology
Tietokannassa oleva lehden nimi: SUPERCONDUCTOR SCIENCE & TECHNOLOGY
Lehden akronyymi: SUPERCOND SCI TECH
Vuosikerta: 20
Numero: 9
Aloitussivu: S159
Lopetussivu: S166
Sivujen määrä: 8
ISSN: 0953-2048
DOI: https://doi.org/10.1088/0953-2048/20/9/S08
Tiivistelmä
Substitutional studies have been carried out on sintered bulk samples of YBCO to determine the effect of doping it with Pr, Ca (at Y site) and Ni (at Cu site) in small concentrations on the formation of effective pinning centres for j(c) enhancement. The results show Pr and Ca substitutions to be far more effective than Ni substitution. The former two give rise to formation of rows of oxygen vacancies with pronounced strain fields in CuO2 planes where superconductivity resides. The defects thus formed seem to be analogous to arrays of normal nanodots in CuO2 planes which are expected to have strong intragrain pinning interactions with pancake vortices of CuO2 planes forming the mixed state structure. Both these substitutions tend to marginalize the adverse effects of grain boundaries. The superconducting volume fraction of the pristine sample is significantly raised by both these substitutions. These special features are, however, absent with Ni substitution. This paper brings out the importance of Pr substitution in significantly enhancing j(c)(B).
Substitutional studies have been carried out on sintered bulk samples of YBCO to determine the effect of doping it with Pr, Ca (at Y site) and Ni (at Cu site) in small concentrations on the formation of effective pinning centres for j(c) enhancement. The results show Pr and Ca substitutions to be far more effective than Ni substitution. The former two give rise to formation of rows of oxygen vacancies with pronounced strain fields in CuO2 planes where superconductivity resides. The defects thus formed seem to be analogous to arrays of normal nanodots in CuO2 planes which are expected to have strong intragrain pinning interactions with pancake vortices of CuO2 planes forming the mixed state structure. Both these substitutions tend to marginalize the adverse effects of grain boundaries. The superconducting volume fraction of the pristine sample is significantly raised by both these substitutions. These special features are, however, absent with Ni substitution. This paper brings out the importance of Pr substitution in significantly enhancing j(c)(B).
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