Superconductivity of amorphous Mg0.70Zn0.30-xGax alloys

The screening. dependence theoretical investigations of the superconducting state parameters (SSP) viz. electron-phonon coupling strength lambda, Coulomb pseuclopotential mu*, transition temperature T-c, isotope effect exponent alpha and effective interaction strength NoV of five Mg0.70Zn0.30-xGax (x = 0.0, 0.06, 0.10, 0.15 and 0.20) ternary amorphous alloys viz. Mg0.70Zn0.30Ga0.00, Mg0.70Zn0.24Ga0.06, Mg0.70Zn0.20Ga0.10, Mg0.70Zn0.15Ga0.15 and Mg0.70Zn0.10Ga0.20 have been reported forthe first time usingAshcroft's empty core (EMC) model potential. Five local field correction functions proposed by Hartree (H), Taylor (T), IchimaruUtsumi (IU), Farid et al. (F) and Sarkar et al. (S) are used in the present investigation to study the screening influence on the aforesaid properties. It is observed that the electron-phonon coupling strength A and the transition temperature Tc are quite sensitive to the selection of the local field correction functions, whereas the Coulomb pseuclopotential mu*, isotope effect exponent a and effective interaction strength NOV show weak dependences on the local field correction functions. The transition temperature Tc obtained from H-local field correction function is found in an excellent agreement with available experimental data. Quadratic Tc equation has been proposed, which provide successfully the Tc values of ternary amorphous alloys under consideration. Also, the present results are found in qualitative agreement with other such earlier reported data, which confirms the superconducting phase in the ternary amorphous alloys. (c) 2008 Elsevier B.V. All rights reserved.