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Origin of peak effect in the magnetization hysteresis loop of melt-processed REBa{sub 2}Cu{sub 3}O{sub y} superconductors

Journal Article · · Applied Physics Letters
DOI:https://doi.org/10.1063/1.120536· OSTI ID:565561
;  [1]; ; ;  [2]; ;  [3]
  1. Defence Metallurgical Research Laboratory, Hyderabad-500 058 (India)
  2. Tata Institute of Fundamental Research, Colaba, Mumbai-400 005 (India)
  3. Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India)
Melt-processed Sm-123 samples with an excess Sm{sub 2}BaCuO{sub y} (Sm-211) phase is studied by transmission electron microscope (TEM) and superconducting quantum interference device magnetometer, to explain the origin of the peak effect exhibited in the magnetization hysteresis loops of light RE-123 samples in intermediate fields at 77 K. TEM images of the sample showing peak effect reveal dilute concentrations of areas with ortho-II structure distributed on a nanometer scale within the twin regions of the sample. The ortho-II structure is an oxygen deficient 123 with a lower T{sub c} than the bulk of the material and will be a source of flux pinning by turning normal in high fields, thus contributing to the peak effect. With an increase in Sm-211 concentration, the peak effect disappears from the hysteresis loop, as does the ortho-II structure in the TEM images. {copyright} {ital 1997 American Institute of Physics.}
OSTI ID:
565561
Journal Information:
Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 26 Vol. 71; ISSN APPLAB; ISSN 0003-6951
Country of Publication:
United States
Language:
English