Laser ablated bismuth cuprate thin films preparation and effect of oxygen nonstoichiometry upon superconductivity

Abstract

Thin films of Bi2Sr2CaCu2O8 and (Bi, Pb)2Sr2Ca2Cu3O10 have been prepared on monocrystalline (100) MgO substrates, using a laser ablation method with post annealing treatment. The influence of substrate temperature and oxygen pressure during deposition were investigated. SEM observations, EDS analysis, electric and magnetic measurements have been used to characterize the films. Superconducting “2212” films, with Tc(R = 0) at 80–83 K and Jc (50 K) up to 5 × 105 A/cm2, have been currently achieved, while Pb-doped “2223” films exhibit Tc as high as 110 K with Jc = 5 × 104 A/cm2 at 77 K. The effect of annealing at low temperature (350°C) in an argon flow has been studied for the 2212 phase, it shows the influence of the oxygen non-stoichiometry, i.e. of the hole carrier density upon Tc's which can be measured up to 89 K (zero resistance).