Evaluation of superconducting gaps in optimally doped Ba(Fe1-xCox)(2)As-2/Fe bilayers by ultrafast time-resolved spectroscopy

Measurements of nonequilibrium quasi-particle relaxation dynamics by using ultrafast pump and probe technique in optimally Co-doped Ba(Fe2As2)/Fe thin film has been reported. Multiple relaxation processes are present with BCS-like temperature-dependent superconducting gaps Delta(0) = (3.67 +/- 0.13) meV and Delta(1) = (6.1 +/- 0.1) meV, which are calculated considering the conventional electron-boson and spin fluctuations pairing mechanism. Then, the value of the electron-phonon coupling constant of lambda = 0.18 has been obtained. (C) 2014 Elsevier B.V. All rights reserved.