Combinatorial solid state chemistry by multitarget laser ablation: a way for the elaboration of new superconducting cuprates thin films?

Laser ablation by varying the number of consecutive laser pulses upon two targets, one superconducting YBa2Cu3O7, the other insulating MCuO2 (M=Sr, Ca), is used to build thin films of tuneable average compositions. Most of the samples are found to display high-Tc superconductivity with critical temperature generally higher than the 60 K of the ‘Cava phase’, the prototypic structure with two consecutive conducting CuO2 planes and containing same types of atoms. The properties of the samples are not linearly dependent on the concentration of species coming from the insulating target. In addition, they depend not only on the ratio of the number of pulses on each target, but also on the number of consecutive pulses on each target. Thin films are characterized by temperature-dependent DC conductivity, X-ray diffraction, Castaing microprobe and infrared reflectivity spectroscopy. Present results suggest the robustness of high-Tc superconductivity, possibly related to a ‘Cava-phase-like’ skeleton.