Various amounts of Si up to a level of 18wt% were added to MgB2 thin films fabricated by pulsed laser deposition. Si was introduced into the pulsed-laser deposition MgB2 films by sequential ablation of a stoichiometric MgB2 target and an Si target. The precursor films were annealed in situ (685C, 60s). Up to an Si level of about 11wt%, the superconducting transition temperature of the film did not change significantly, as compared to the undoped film. The magnetic critical current density of the film at 5K was increased by 50% with about 3.5wt%Si addition, as compared to the undoped film. The slope of Hirr(T) and HC2(T) curves of the 3.5wt%Si added MgB2 film was slightly higher than that for the undoped film.

Si Addition in in situ Annealed MgB2 Thin Films by Pulsed Laser Deposition. Y.Zhao, M.Ionescu, J.Horvat, A.H.Li, S.X.Dou: Superconductor Science and Technology, 2004, 17, 1247-52