A5019189884- Magnetic and transport properties of perovskites and related materials
- Electronic and Structural Properties of Oxides
- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- Advancements in Solid Oxide Fuel Cells
- Diamond and Carbon-based Materials Research
- ZnO doping and properties
- Catalytic Processes in Materials Science
- Semiconductor materials and devices
- Copper-based nanomaterials and applications
- Metal and Thin Film Mechanics
- Magnetic properties of thin films
- Fuel Cells and Related Materials
- Multiferroics and related materials
- Ferroelectric and Piezoelectric Materials
- Iron-based superconductors research
- High-pressure geophysics and materials
- Magnetic Properties and Synthesis of Ferrites
- Electrocatalysts for Energy Conversion
- Surface and Thin Film Phenomena
- Advanced Chemical Physics Studies
- Nuclear materials and radiation effects
- Machine Learning in Materials Science
- X-ray Spectroscopy and Fluorescence Analysis
- Advancements in Battery Materials
University of Rome Tor Vergata
2014-2025
European University of Rome
2018
Superconducting and other Innovative Materials and Devices Institute
2012-2018
National Research Council
2014-2016
European Synchrotron Radiation Facility
2012
École Nationale Supérieure d'Ingénieurs de Caen
2012
Laboratoire de Cristallographie et Sciences des Matériaux
2012
Centre National de la Recherche Scientifique
2012
Istituto Nazionale per la Fisica della Materia
2004
Instituto Politécnico Nacional
2004
Linear dichroism (LD) in x-ray absorption, diffraction, transport, and magnetization measurements on thin La(0.7)Sr(0.3)MnO(3) films grown different substrates, allow identification of a peculiar interface effect, related just to the presence interface. We report LD signature preferential 3d-e(g)(3z(2)-r(2)) occupation at interface, suppressing double exchange mechanism. This surface orbital reconstruction is opposite that favored by residual strain independent dipolar fields, chemical...
SrTiO(3)/LaAlO(3) interfaces show an unprecedented photoconductivity effect that is persistent even at room temperature and giant as it gives rise to a conductivity increase of about 5 orders magnitude temperature. The effects play paramount role in the still controversial intrinsic behavior interfaces, limited exposure visible light able strongly modify electrical transport properties interface above temperature, while only appropriate thermal treatment dark environment can completely...
Strain induced anisotropy in the electronic properties of ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}\mathrm{Mn}{\mathrm{O}}_{3}$ thin films was investigated by x-ray absorption spectroscopy at Mn $2p$ and O $1s$ edges. Films on (100) $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$ $\mathrm{La}\mathrm{Al}{\mathrm{O}}_{3}$ substrates were grown pulsed laser deposition with situ reflection high energy electron diffraction diagnostic. At both edges, clear features related to different anisotropic lattice...
Superlattices of samarium-doped ceria (SDC)/yttria-stabilized zirconia (YSZ) are grown by pulsed laser deposition on (001) MgO with a SrTiO3 buffer layer. The ionic conductivity shows sizeable increase relative to SDC and YSZ bulk values. Such an enhancement is attributed the epitaxial strain, effect that mostly confined in layers.
Abstract Thin films of samarium‐oxide‐doped (20 mol%) ceria (SDC) are grown by pulsed‐laser deposition (PLD) on (001) MgO single‐crystal substrates. SrTiO 3 (STO) prepared PLD is used as a buffer layer the substrates to enable epitaxial growth fluorite‐structured SDC film; STO provides proper crystalline match between and MgO, resulting in highly crystalline, orientation. Film conductivity evaluated electrochemical impedance spectroscopy measurements, which performed at various temperatures...
In this paper, we illustrate an approach to discriminate between epitaxial strain and other factors responsible for the decrease of metal–insulator transition temperature (TP) in thin La0.7Sr0.3MnO3 films grown by pulsed laser deposition. Using approach, have estimated effect biaxial on TP. Ultrathin films, independent strain, do not show any over full range. This finding confirms existence interface dead layer. The strain-independent TP, relative its bulk value, observed a much wider...
We have performed x-ray linear and circular magnetic dichroism experiments at the $\text{Mn}\text{ }{L}_{2,3}$ edge of ${\text{La}}_{0.7}{\text{Sr}}_{0.3}{\text{MnO}}_{3}$ ultrathin films. Our measurements show that antiferromagnetic (AF) insulating phase is stabilized by interfacial rearrangement }3d$ orbitals, despite relevant magnetostriction anisotropic effect on double-exchange ferromagnetic (FM) metallic phase. As a consequence, Mn atomic magnetic-moment orientation how it reacts to...
${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}\mathrm{Mn}{\mathrm{O}}_{3}$ thin films having different thicknesses were grown by pulsed laser deposition with in situ reflection high energy electron diffraction diagnostics on $\mathrm{La}\mathrm{Al}{\mathrm{O}}_{3}$ substrates. The mismatch between film and substrate gives rise to an in-plane compressive biaxial strain, which partially relaxes thicker than $30\phantom{\rule{0.3em}{0ex}}\text{unit}$ cells. Accordingly, the ratio out-of-plane lattice...
We have grown LaMnO3 thin films on (001) LaAlO3 substrates by pulsed laser deposition. X-ray diffraction confirms that the are only slightly relaxed and oriented “square square” relative to substrate. The measured Raman spectra closely resemble observed in bulk LaMnO3, which indicates no relevant distortions of MnO6 octahedra induced epitaxial strain. Therefore, detectable changes lattice dynamics occurred our strained case. Mn55 nuclear magnetic resonance identifies presence localized Mn4+...
From recent literature, it became clear that the crystallographic lattice parameters and superconducting properties of FeSe0.5Te0.5 thin films exhibit a non-trivial dependence on in-plane constant substrates which they are grown. The strain, depends type growth, can play an important role both in enhancing critical temperature Tc determining pinning mechanisms. Here, we present effects substrate films. After comprehensive overview different used, i.e. oxides fluorides, compare grown...
We report the occurrence of superconductivity, with maximum Tc = 40 K, in superlattices (SLs) based on two insulating oxides, namely CaCuO2 and SrTiO3. In these (CaCuO2)n/(SrTiO3)m SLs, CuO2 planes belong only to block, which is an antiferromagnetic insulator. Superconductivity, confined within few unit cells at CaCuO2/SrTiO3 interface, shows up when SLs are grown a highly oxidizing atmosphere, because extra oxygen ions entering interfaces. Evidence reported that hole doping obtained by...
We report the momentum-resolved measurement of a two-dimensional electron gas at LaTiO(3)/SrTiO(3) interface by angle-resolved photoemission spectroscopy (ARPES). Thanks to an advanced sample preparation technique, orbital character conduction electrons and electronic correlations can be accessed quantitatively as each unit cell layer is added. find that all these quantities change dramatically with distance from interface. These findings open way analogous studies on other heterostructures,...
At interfaces between complex oxides it is possible to generate electronic systems with unusual properties, which are not present in the isolated oxides. One important example appearance of superconductivity at interface insulating oxides, although, until now, very low T(c). We report occurrence high T(c) bilayer CaCuO(2)/SrTiO(3), where both constituent insulating. In order obtain a superconducting state, CaCuO(2)/SrTiO(3) must be realized Ca plane CaCuO(2) and TiO(2) SrTiO(3). Only this...
We have studied the emission spectra from plasmas excited in several compositions of three different gas mixtures useful for growth diamond films, namely CH4-H2 (the classical one), CH4-CO2 and C2H2-CO2 (not previously reported by other authors). In all cases we find same correlation between quality obtained films some spectral features: particular, yield best corresponds to presence line at wavelength 431 nm ascribed CH, absence band 505–517 attributed C2. The appearance progressive...
A systematic study by reversible and hysteretic electrochemical strain microscopy (ESM) in samples of cerium oxide with different Sm content several working conditions allows disclosing the microscopic mechanism underlying difference electrical conduction related surface activity, such as water adsorption dissociation subsequent proton liberation. We have measured behavior hysteresis loops changing temperature humidity, both standard ESM configuration using first-order reversal curve method....
We performed in situ angle-resolved photoemission spectroscopy measurements on ${\text{La}}_{2/3}{\text{Sr}}_{1/3}{\text{MnO}}_{3}$ thin and ultrathin films deposited onto ${\text{SrTiO}}_{3}$ substrates order to determine their electronic band structure. directly identified, films, an enhancement of the occupation out-of-plane $\text{Mn}\text{ }3d\text{ }{e}_{g}$ $(3{z}^{2}\ensuremath{-}{r}^{2})$ at expense in-plane $3d\text{ $({x}^{2}\ensuremath{-}{y}^{2})$ band. Such a disproportionate...
Spinel-type lithium manganese oxide (LiMn2O4) is considered one of the most promising cathode materials for rechargeable batteries due to its high operating voltage, reduced toxicity, and lower cost compared cobalt-based cathodes. However, stability LiMn2O4 a significant challenge, as it tends degrade over time, with ion segregation leading reduction in battery capacity.
Epitaxial layers of water-soluble Sr3Al2O6 were fabricated as sacrificial on SrTiO3 (100) single-crystal substrates using the Pulsed Laser Deposition technique. This approach envisages possibility developing a new generation micro-Solid Oxide Fuel Cells and Electrochemical for portable energy conversion storage devices. The layer technique offers pathway to engineering free-standing membranes electrolytes, cathodes, anodes with total thicknesses order few nanometers. Furthermore, ability...
The infinite layer structure of CaCuO2 (CCO) represents a benchmark system for exploring the physics CuO2 planes, which play fundamental role in superconductive behavior at high critical temperature cuprates. In this work, we carried out an extensive investigation Raman spectrum epitaxial films CCO by varying degree and origin disorder crystal lattice. A stoichiometric film synthesized on [LaAlO3]0.3[Sr2AlTaO6]0.7 substrate served as reference to account nearly ideal behavior, while...
Yttrium-doped barium zirconate (BZY) thin films recently showed surprising electric transport properties. Experimental investigations conducted mainly by electrochemical impedance spectroscopy suggested that a consistent part of this BZY conductivity is protonic nature. These results have stimulated further local unconventional techniques. Here, we use strain microscopy (ESM) to detect activity in with nanoscale resolution. ESM novel cross-sectional measuring setup allows the direct...
A study of the structure and transport properties highly textured, epitaxial oriented BaZr0.8Y0.2O3−x thin films grown on NdGaO3(110) is reported. Films have been by pulsed laser deposition their conductivity studied as a function temperature thickness. The results show an increased conductance sample thickness decreases. measured corresponding to in-plane 20 S cm−1 has systematically observed in range 550–600 °C for several 10 nm-thick films. high values are possibly related densities...
High quality epitaxial films of the ‘infinite layer’(IL) compound SrxCa1 –xCuO2(x= 0–1) have been grown by pulsed laser deposition on NdGaO3(110) substrates, thus including last member this series CaCuO2, for first time, to our knowledge. The varied with composition: higher were obtained x= 0 and 0.1. experimental results explained taking into account lattice match between film substrate: a better in quality. A very good is NdGaO3 substrates IL small or zero Sr content. Attempts grow also...
Here we report on interface reconstruction in the recently discovered superconducting artificial superlattices based insulating ${\mathrm{CaCuO}}_{2}$ and ${\mathrm{SrTiO}}_{3}$ blocks. Hard x-ray photoelectron spectroscopy shows that valence-band alignment prevents any electronic by direct charge transfer between two We demonstrate electrostatic built-in potential is suppressed oxygen redistribution alkaline-earth-metal planes. By using highly oxidizing growth conditions, coordination...