A series of superconducting La 2−x Sr x CuO 4 thin films, with 0.09 x 0.22, is grown over (100)SrTiO 3 substrates by means of a novel pulsed laser deposition method devised to increase the homogeneity and control of doping. We employ two separate parent oxide targets that receive ablation shots at arbitrary computer-controlled relative rates, instead of the conventional procedure that uses a single target whose doping determines the one of the film. We characterize the films both through conventional techniques (XRD, SEM, AFM and EDX) and by measuring their superconducting transition with a high-sensitivity SQUID magnetometer. The latter allows one to determine not only their average critical temperatures Tc (x) but also their dispersions due to inhomogeneities, T c (x). For Tc (x) we obtain the conventional parabolic law centered at x = 0.16, plus a Gaussian depression near x = 1/8 with a Tc -height of about 5 K and x-width about 0.03. For T c (x) we obtain, for all the dopings, values among the lowest reported up to now for La 2−x Sr x CuO 4 . The T c (x) dependence can be explained in terms of the unavoidable randomness of the positioning of the Sr ions (the so-called intrinsic chemical inhomogeneity) and a separate residual T c -inhomogeneity contribution of the order of 0.5 K, this last associated with the samples' structural inhomogeneities and films' substrate.

Gadolinia Doped Ceria (GDC) buffer layers were synthesized by reactive magnetron sputtering under different bias powers applied to the substrate holder. All as-deposited coating present a face centered cubic (f.c.c) structure of ceria with dense and adhesive morphology. Only the film deposited under 80 W bias power applied to the substrate does not exhibit cracks after an annealing treatment during 2 h under air at 1000°C. The performance of the cell is 670 mW.cm -2 @ 800 mA.cm -2 at 790°C and no degradation was observed after 150 hours.

The new results summarized here, including a brief comparison with the paraconductivity, further suggest that the anomalous precursor (above T c ) diamagnetism recently observed in the underdoped La 1.9 Sr 0.1 CuO 4 superconductor could be attributed to the presence, in addition to the conventional superconducting pair fluctuations, of T c -inhomogeneities with long characteristic lengths associated with chemical disorder .