We report on epitaxial growth of Bi₂Se₃ topological insulator thin films by Pulsed Laser Deposition (PLD). X-ray diffraction investigation confirms that Bi₂Se₃ with a single (001)-orientation can be obtained on several substrates in a narrow (i.e., 20 °C) range of deposition temperatures and at high deposition pressure (i.e., 0.1 mbar). However, only films grown on (001)-Al₂O₃ substrates show an almost-unique in-plane orientation. In-situ spin-resolved angular resolved photoemission spectroscopy experiments, performed at the NFFA-APE facility of IOM-CNR and Elettra (Trieste), show a single Dirac cone with the Dirac point at $E_B\sim 0.38$ eV located in the center of the Brillouin zone and the spin polarization of the topological surface states. These results demonstrate that the topological surface state can be obtained in PLD-grown Bi₂Se₃ thin films.

The metal-insulator transition (MIT) has been studied in ${\mathrm{Ba}}_{0.9}{\mathrm{Nd}}_{0.1}{\mathrm{CuO}}_{2+x}/{\mathrm{CaCuO}}_2$ ultrathin cuprate structures. Such structures allow for the direct measurement of the 2D sheet resistance $R_{\square }$, eliminating ambiguity in the definition of the effective thickness of the conducting layer in high temperature superconductors. The MIT occurs at room temperature for experimental values of $R_{\square }$ close to the $25.8\mathrm{k}\Omega$ universal quantum resistance. All data confirm the assumption that each ${\mathrm{CaCuO}}_2$ layer forms a 2D superconducting sheet within the superconducting block, which can be described as weak-coupled equivalent sheets in parallel.

We have fabricated ${\text{La}}_{0.7}{\text{Ba}}_{0.3}{\text{MnO}}_3$ (LBMO) thin films by a pulsed laser deposition technique using a low partial pressure $\left({10}^{-2}\text{mbar}\right)$ of ${\text{O}}_2+5\%{\text{O}}_3$ . In order to study the role of oxygen content in the transport properties, the temperature dependence of the resistivity has been measured as a function of the temperature and the time of a post-annealing process. Strain-less LBMO thin films deposited on ${\text{SrTiO}}_3$ substrates show a metal insulator transitions temperature $T_{\text{MI}}\simeq 345\text{K}$ (equal to that found in bulk material). A $T^{2.5}-\text{power}$ law has been measured in $R\left(T\right)$ at low temperature, supporting the disorder-induced single magnon scattering scenario. At high temperature $\left(T>T_{\text{MI}}\right)$ an activated behavior characteristic of polaronic carriers has been measured. Magnetotransport properties show a metal-like behavior and a negative magnetoresistance (MR) in the whole temperature range. With an external magnetic field of $70\text{kOe}$ , the MR reaches the maximum value of $170\%$ at about $320\text{K}$ .

The use of a doped Ceria buffer layer and Physical Vapour Deposition (PVD) techniques for Solid Oxide Fuel Cells (SOFC) fabrication can limit the former, the formation of electrical insulating lanthanum, and strontium zirconates at the cathode/electrolyte interface, whereas the latter allows a better control of the materials interfaces. These effects allow for operation at intermediate temperature ranges. In this work, we study the structural and electrical properties of Gadolinium Doped Ceria (GDC) barrier layer deposited via the room temperature RF Sputtering technique on anode supported electrolytes and then annealed at high temperature. The crystal structure and the surface morphology of the GDC barrier layers have been analyzed and optimized varying the temperature ramp of the post-growth annealing procedure. The electrical behavior of the obtained samples has been investigated by Electrochemical Impedance Spectroscopy and compared to that of standard SOFC with screen-printed GDC barrier layers, the former showing a maximum high frequency and low frequency resistances reduction of about 50% and 46%, respectively, with respect to the latter at an operating temperature of 650 °C. The results clearly show an important improvement of SOFC performances when using sputter deposited GDC layers, linking the electrical properties to the structural and stoichiometric ones.

Due to their interesting ferroelectric, conductive and dielectric properties, in recent years, perovskite-structured materials have begun to attract increasing interest in the biosensing field. In this study, a strontium titanate perovskite layer (SrTiO₃) has been synthesized on a platinum electrode and exploited for the development of an impedimetric label-free immunosensor for Escherichia coli O157:H7 detection. The electrochemical characterization of the perovskite-modified electrode during the construction of the immunosensor, as well as after the interaction with different E. coli O157:H7 concentrations, showed a reproducible decrease of the total capacitance of the system that was used for the analytical characterization of the immunosensor. Under optimized conditions, the capacitive immunosensor showed a linear relationship from to 1 to 7 log cfu/mL with a low detection limit of 1 log cfu/mL. Moreover, the atomic force microscopy (AFM) technique underlined the increase in roughness of the SrTiO₃-modified electrode surface after antibody immobilization, as well as the effective presence of cells with the typical size of E. coli.