The effect of chemical inhomogeneities on the pinning properties of Bi2212 single crystals

Noriko Chikumoto, Kimiyasu Furusawa, Masato Murakami

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Abstract

We have carried out a detailed characterization of chemical inhomogeneities in Bi2212 single crystals grown by a floating zone method. According to the chemical analyses using WDS, there are two types of inhomogeneities; one with linear structures extending toward the a-axis, and another with sheet-like structures that lying along the a-axis. The line defects relate to compositional inhomogeneities, such as Ca-enriched or Ca-deficient regions, with widths ranging from a few nanometres to micrometres and lie parallel to the crystal a-axis. From the observation of local flux line arrangement using a Bitter decoration technique and a magneto-optical imaging technique, the flux line arrangement at the defect region is largely affected by the type of nonstoichiometry involved. We found that the flux-line lattice at the Ca-enriched region has a hexagonal order with small scattering, while that at the Ca-deficient region is amorphous. On the other hand, the crystal with sheet-like inhomogeneities showed a 'zebra-like' flux penetration and trapping behaviour. This result suggests that the samples are composed of two kinds of regions with completely different pinning properties.

Original languageEnglish
JournalSuperconductor Science and Technology
Volume17
Issue number2
DOIs
Publication statusPublished - 2004 Feb
Externally publishedYes

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ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)
  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

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