Controllable Formation of Particulates and the Effects on Superconductivity of La1.85Sr0.15CuO4 Film Grown by the Pulsed Electron Deposition Method

During the growth of La1.85Sr0.15CuO4 (LSCO) film by pulsed electron deposition, the formation of surface particulates shows a strong dependence on several key factors, such as the substrate, the deposition pressure (P), and the accelerating potential (AP). The size of the particulates can be controlled through finely tuning either P or AP, thus offering a possible route toward producing nanoparticles for practical uses. An ordered linear structure promising in design superconducting devices was observed when LSCO was grown on silicon substrate, originating with the large lattice parameters mismatch between the substrate and film. Superconductivity of the LSCO film shows a strong sensitivity to both the amount and size of the particulates. The underlying mechanism was discussed in connection with theories of lattice distortion and tunneling transport across grain boundaries.