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Paramagnetic Resonance Studies of Phase Separation in Cuprate Superconductors

  • O. F. Schirmer
  • G. Wübbeler
  • Th. Wahlbrink
Conference paper

Summary

Using paramagnetic resonance techniques phenomena are identified in La2CuO4+δ ceramics which support the phase separation model. A signal near B = 0, proportional to the superconducting volume fraction, decreases after heating to T i ≥ 270 K and fast quenching to 4.2 K and a new signal, related to Cu2+, appears. The initial intensities are approached under annealing at T an ≥ 200 K. In single crystal La2CuO4+δ the Cu2+ related signal is not observed. La2−x Sr x CuO4+δ ceramic does not show any of the indicated responses. The effects can be attributed to evaporation of spin polarized clusters from a percolating network of metallic - and below T c superconducting - paths under heating and subsequent quenching and condensation into such paths under annealing. The origin of the Cu2+ related signal is discussed.

Keywords

Electron Paramagnetic Resonance Excess Oxygen Isochronal Anneal Signal Height Diamagnetic Susceptibility 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1994

Authors and Affiliations

  • O. F. Schirmer
    • 1
  • G. Wübbeler
    • 1
  • Th. Wahlbrink
    • 1
  1. 1.University of OsnabrückOsnabrückGermany

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