Effect of oxygen deficiency (δ) on normal state resistivity of YBa2Cu3O7δ superconductors

We have investigated theoretically the effect of oxygen deficiency δ on normal state resistivity (ρ) as well as its temperature dependence in YBa2Cu3O7-δ superconductors. This has been based on a potential which incorporates the structure factors and various interactions for double two-dimensional (2-D) conducting CuO2 plane. Using the coulomb and electron-phonon terms of the interaction potential, we have then worked out the coupling strength (γ) for neighbouring electrons linked via 2-D acoustic phonons (hω). Furthermore, the scattering time (τe-ph) due to electron-phonon interaction is deduced. The variations in τe-ph and ρeph are studied with oxygen deficiency δ which is in the range of 0.0≤δ≤1.0, and the results thus obtained are found to be consistent with the earlier reported data. The residual resistivity ρ0 obtained by extrapolation from experimental data together with ρe-ph will predict the nearly-linear behaviour of normal state resistivity at temperatures (T) [90≤T≤300K] in YBa2Cu3O7-δ superconductors. (author)