Oxygen deficiency dependence of transition temperature in (Sm, Er) Ba2Cu3O7−δ superconductors
- 22 Downloads
We have investigated the effects of oxygen deficiency (δ) on the transition temperature (T c) of (Sm, Er)Ba2Cu3O7− δ superconductors by incorporating the effects of the two dimensional (2D) acoustic phonons and plasmons in the framework of strong coupling theory. The proposed approach for yttrium cuprates properly takes care of the double CuO2 plane in a unit cell and has been found earlier to be successful in describing the pairing mechanism as well as the variation ofT c withδ in Y Ba2Cu3O7− δ system. The coupling strength (λ), the screening parameter (μ*) and the two dimensional acoustic phonon (plasmon) energyħω −(ω+) as a function of oxygen deficiency is worked out. Finally, the transition temperature is evaluated and is found to be consistent with the earlier experimental data on yttrium cuprates. Thus, coupled phonon-plasmon mechanism is adequate to understand the nature of pairing mechanism and oxygen deficiency dependence of transition temperature in 90 K (Sm, Er)Ba2Cu3O7− δ superconductors.
KeywordsOxygen deficiency transition temperature coupling strength screening parameter yttrium cuprates
Unable to display preview. Download preview PDF.
- Bozovic I 1990Phys. Rev. B42 1969Google Scholar
- Elishberg G M 1960Sov. Phys. (JETP) 11 696Google Scholar
- Kerkels T, Zou H, Ven Tendeloo G, Wagener D, Buchgeister M, Hosseini S M and Herzog P 1992Physica C196 363Google Scholar
- Kresin V Z 1987Phys. Rev. B35 3116Google Scholar
- Molokac S, Flachbart K, Bischof J and Belling A 1990Physica B165–166 1205Google Scholar
- Ruvalds J 1987Phys. Rev. B35 8869Google Scholar
- Tarascan J M, Mckinon W R, Grene L H, Hull G W and Vogel E M 1987Phys. Rev. B36 226Google Scholar
- Varshney Dinesh and Singh R K 1995Phys. Rev. B52 7629Google Scholar