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Effect of oxygen concentration in the sputtering gas and effect of substrate type on the electrical resistance of Bi:2201 nanoscale thin films

“…The linear dependence of ρ(T) as function of ln T agrees with a non-Fermi liquid model with a singular density of states in the presence of randomly nonmagnetic impurities [16].…”

“…The normalized conductivity (σ/σ op ) 300 K (were σ op is the conductivity for optimal doping) was used to characterize the oxygen doping [11,16]. For our studies (σ op ) 300 is the conductivity of the thin film deposited onto SrTiO 3 substrate at f O 2 = 0.5.…”

“…The plot gave almost a straight line in the temperature range 7-34 K for f O 2 = 0.4 and in the ranges 12-34 K (MgO substrate), 13-34 K (SrTiO 3 substrate) for f O 2 = 0.35, respectively. Previously, results for a linear dependence of ρ versus ln T were reported only below T = 20 K. The logarithmic temperature dependence of electrical resistance was obtained taking into consideration a model of strong correlated electronic system with a single particle self-energy of the marginal Fermi liquid, and in the presence of randomly distributed nonmagnetic impurities, [16]. The density of states has the form of a power law energy dependence:…”