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Doppler broadening measurements of the electron-positron annihilation radiation in La 0.7Y 0.3Ca 0.5Ba 1.5Cu 3O z superconductor
M CHAKRABARTI, K R MAVANI, S CHATTOPADHYAY, A SARKAR, D SANYAL
Published in -
2004
Volume: 329
   
Issue: 3
Pages: 231 - 235
Abstract
Background-suppressed Doppler broadening spectroscopy, using two detector coincidence technique of the electron-positron annihilation γ-radiation, has been employed on tetragonal La 0.7Y 0.3Ca 0.5Ba 1.5Cu 3O z polycrystalline high-Tc superconductor to study the changes in the electron momentum distributions due to superconducting transition. The temperature-dependent (298 K to 60 K) S-parameter graph shows a sharp peak at the superconducting transition temperature, Tc, region. The spectra at different sample temperatures have been compared with the spectra of defect-free 99.9999% pure Al and Cu metals by constructing ratio-curves. The results indicate a decrease of the annihilation of positrons with 3d electrons of Cu ions just above Tc. © 2004 Elsevier B.V. All rights reserved.
About the journal
JournalPhysics Letters, Section A: General, Atomic and Solid State Physics
Publisher-
ISSN0375-9601