RESUMEN
The realization of perovskite oxide nanostructures with controlled shape and dimensions remains a challenge. Here, we investigate the use of helium and neon focused ion beam (FIB) milling in an ion microscope to fabricate BaTiO3nanopillars of sub-500 nm in diameter starting from BaTiO3(001) single crystals. Irradiation of BaTiO3with He ions induces the formation of nanobubbles inside the material, eventually leading to surface swelling and blistering. Ne-FIB is shown to be suitable for milling without inducing surface swelling. The resulting structures are defect-free single crystal nanopillars, which are enveloped, on the top and lateral sidewalls, by a point defect-rich crystalline region and an outer Ne-rich amorphous layer. The amorphous layer can be selectively etched by dipping in diluted HF. The geometry and beam-induced damage of the milled nanopillars depend strongly on the patterning parameters and can be well controlled. Ne ion milling is shown to be an effective method to rapidly prototype BaTiO3crystalline nanostructures.
RESUMEN
A custom CMOS image sensor hardened by design is characterized in a transmission electron microscope, with the aim to extract basic parameters such as the quantum efficiency, the modulation transfer function and finally the detective quantum efficiency. In parallel, a new methodology based on the combination of Monte Carlo simulation of electron distributions and TCAD simulations is proposed and performed on the same detector, and for the first time the basic parameters of a direct CMOS electron detector are extracted thanks to the TCAD. The methodology is validated by means of the comparison between experimental and simulation results. This simulation method may be used for the development of future electron detectors.
RESUMEN
CoPt and FePt nanostructures have been efficiently confined in carbon nanotubes (CNTs). A marked confinement effect has been evidenced, both on bimetallic nano-object shape and composition. In large diameter CNTs small Co- and Fe-rich nanoparticles are formed, while in small diameter CNTs Pt-rich nanowires are selectively produced.
RESUMEN
Using neutron reflectometry and resonant x-ray techniques we studied the magnetic proximity effect (MPE) in superlattices composed of superconducting YBa2Cu3O7 and ferromagnetic-metallic La0.67Ca0.33MnO3 or ferromagnetic-insulating LaMnO(3+δ). We find that the MPE strongly depends on the electronic state of the manganite layers, being pronounced for the ferromagnetic-metallic La0.67Ca0.33MnO3 and almost absent for ferromagnetic-insulating LaMnO(3+δ). We also detail the change of the magnetic depth profile due to the MPE and provide evidence for its intrinsic nature.
