Pinning mechanisms in bulk high-Tc superconductors

M. R. Koblischka, M. Murakami

研究成果: Conference article査読

106 被引用数 (Scopus)

抄録

Volume pinning forces are determined for a variety of bulk high-Tc superconductors of the 123 type from magnetization measurements. By means of scaling of the pinning forces, the acting pinning mechanisms in various temperature ranges can be identified. The Nd-based superconductors and some YBCO crystals exhibit a dominating pinning of the δTc type (i.e. small, superconducting pinning sites). This is ascribed to the presence of an Nd-rich phase with weaker superconducting properties, leading to a spatial scatter of Tc, which can also be provided by oxygen vacancy clusters. In contrast to this, the addition of insulating 211 particles provides pinning of the δl type. Measurements of the field-cooled magnetization show that the Nd-based superconductors exhibit two-step transitions if cooled/warmed in fields above 4 T. This secondary transition can be correlated to the peak effect. This suggests that the peak effect is an unique property of the superconducting matrix (i.e. oxygen vacancy clusters), whereas the 211 particles provide effective pinning in the entire temperature range acting as a quasi-'background' pinning mechanism for the peak effect. Based on these observations we construct a pinning force diagram for bulk high-Tc superconductors.

本文言語English
ページ(範囲)738-744
ページ数7
ジャーナルSuperconductor Science and Technology
13
6
DOI
出版ステータスPublished - 2000 6 1
外部発表はい
イベントThe 2nd International Workshop on the Processing and Applications of Superconducting (RE)CBO Large Grain Materials - Morioka, Jpn
継続期間: 1999 10 191999 10 22

ASJC Scopus subject areas

  • セラミックおよび複合材料
  • 凝縮系物理学
  • 金属および合金
  • 電子工学および電気工学
  • 材料化学

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