Variation of the in-plane penetration depth lambda(ab) as a function of doping in La2-xSrxCuO4+/-delta thin films on SrTiO3: Implications for the overdoped state

Normal-state properties, such as the resistivity rho(ab) and the Hall coefficient R(H), structural properties, such as the c axis and in-plane lattice parameters, and superconductive properties, such as the critical temperature T-c, the penetration depth lambda(ab), and the thermal activation energy for flux flow Delta U, are reported for c-axis La2-xSrxCuO4+/-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 T-c, Delta U, and lambda(ab)(-1) are observed close to optimum doping, while R(H) and rho(ab) decrease monotonically.