Fabrication of cobalt-doped SrFe2As2 superconducting thin films

We have fabricated Co-doped bilayered SrFe2As2 thin films on Al2O3 (0 0 0 1) and LaAlO3 (0 0 1) substrates by using a pulsed laser deposition (PLD) technique with a 248-nm-wavelength KrF excimer laser. In order to fabricate Co-doped SrFe2As2 thin films, we used homemade target with an As-rich phase. We tried to find optimum growth condition by changing various experimental conditions, such as substrate temperature and laser energy density. The superconducting transition temperatures were influenced by growth temperature, but hardly affected by laser energy density. The best sample showed the Tc of ∼20 K with a narrow superconducting transition width of 2.2 K.