Variation of the In-plane Penetration Depth lambda(ab) as a Function of Doping in La(2-x)Sr(x)CuO(4+/- delta) Thin Films on SrTiO(3)

Normal-state properties, such as the resistivity rho(ab) and the Hall coefficient R(Hh), structural properties such as the c-axis and in--plane lattice parameters, and superconductive properties, such as the critical temperature Tc, the penetration depth lambda(ab) and the thermal activation energy for flux flow Delta U, are reported for c-axis La(2-x)Sr(x)CuO(4+/-delta films. These parameters have been measured as a function of doping in the range from heavily underdoped to heavily overdoped. The structural data indicate a 0.3% compression of the c-axis parameter and a corresponding 0.3% expansion of the in-plane lattice parameters as compared to bulk values, which explains the overall reduced critical temperature of these thin films. As the dopant content is increased, maximum values for Tc, Delta U and lambda(ab)**-1 are observed close to optimum doping, while R(H) and rho(ab) decrease monotonically. The observed behavior in the overdoped regime suggests an increase of the effective mass and/or a decrease of the superfluid density with increased doping.