Magneto-optical and high resolution electron microscopy studies of flux pinning at grain boundaries in Bi2Sr2CaCu2O<i>x</i> crystals

Egi, Toshio; Wen, Jing; Kubota, Hitoshi; Ricketts, J.; Koshizuka, N.

doi:10.1063/1.114139

Cited by 8 publications

(3 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For multicrystalline samples the description in terms of pinning inside the grain boundary is also useful. It was successfully applied to the analysis of critical current in Bi-2223 tapes in [125].…”

Section: Pinning By Point Defects and Nonuniformitiesmentioning

confidence: 99%

Introduction of pinning centres into Bi - (Pb) - Sr - Ca - Cu - O superconductors

Dou

Wang

Guo

et al. 1997

Supercond. Sci. Technol.

View full text Add to dashboard Cite

High critical current density is essential for most large-scale applications of high-temperature superconductors (HTSs). In addition to the weak link problem, weak flux pinning is a major cause of the rapid decline of with magnetic field at high temperatures. Through intensive research in the past 10 years the weak pinning problem has been partially overcome and has reached a level approaching the requirement for some commercial applications. In this article, a number of techniques by which effective pinning centres can be introduced to improve flux pinning in Bi - (Pb) - Sr - Ca - Cu - O HTSs are reviewed. These include surface pinning through a spiral growth, fine precipitates produced through phase transformation or phase formation - decomposition, inclusions through chemical doping or addition, cascades and columnar defects created by fast-neutron and heavy ion beam irradiation and various defects induced by mechanical deformation. In particular, the results of Bi-2223 formation - decomposition and cold deformation versus hot deformation have a significant implication for HTS wire fabrication. Comparative studies with comprehensive electrical, magnetic and microstructural characterizations have been carried out to assess the effectiveness of these techniques.

show abstract

Section: Pinning By Point Defects and Nonuniformitiesmentioning

confidence: 99%

Introduction of pinning centres into Bi - (Pb) - Sr - Ca - Cu - O superconductors

Dou

Wang

Guo

et al. 1997

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…It is not clear what these defects are. They may be amorphous patches along small-angle grain boundaries [35], or dislocations, for example. Low-angle tilt boundaries are strong links and they conduct current at elevated fields.…”

Section: Discussionmentioning

confidence: 99%

Improvement of flux pinning by thermo-mechanical treatment of Bi-2223/Ag superconducting tapes

Horvat

Bhasale

Guo

et al. 1997

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Measurements of the transport critical current in a magnetic field (H), hysteresis loops and a.c. susceptibility were performed on Bi-2223/Ag tapes that were subjected to different degrees of mechanical deformation and subsequently sintered. against H for some of the tapes was also measured at different stages of thermo-mechanical treatment. All the measurements (the field of the peak of the pinning force, the irreversibility field obtained from hysteresis loops and the temperature of the peak of a.c. susceptibility for different d.c. fields) clearly show an increase of pinning with increase of the degree of mechanical deformation. Measurements of samples at different stages of thermo-mechanical treatment indicate that the pinning depends not only on the degree of mechanical deformation, but also on the conditions of the grain growth. Sintering can provide imperfect healing of micro- and nano-cracks, introduced upon mechanical deformation. It is proposed that the imperfections introduced by the healing are responsible for the improvement in flux pinning, and not the dislocations introduced upon mechanical deformation.

show abstract

“…It has been shown that grain boundaries, growth dislocations, crystal structural non-uniformities, impurity phases, precipitates, oxygen vacancies and other microstructural defects can act as effective pinning centers in Bi-based high temperature superconductors [4][5][6][7][8][9]. The introduction of correlated defects such as columnar defects can resist the thermally activated flux flow at high temperatures successfully.…”

Section: Introductionmentioning

confidence: 98%

Flux pinning properties of magnesium diboride added (Bi,Pb)-2212 superconductors

Vinod

Kumar

Biju

et al. 2007

Journal of Alloys and Compounds

View full text Add to dashboard Cite

Magneto-optical and high resolution electron microscopy studies of flux pinning at grain boundaries in Bi2Sr2CaCu2Ox crystals

Cited by 8 publications

References 6 publications

Introduction of pinning centres into Bi - (Pb) - Sr - Ca - Cu - O superconductors

Introduction of pinning centres into Bi - (Pb) - Sr - Ca - Cu - O superconductors

Improvement of flux pinning by thermo-mechanical treatment of Bi-2223/Ag superconducting tapes

Flux pinning properties of magnesium diboride added (Bi,Pb)-2212 superconductors

Contact Info

Product

Resources

About