A5002255299- Iron oxide chemistry and applications
- Magnetic Properties and Synthesis of Ferrites
- Glass properties and applications
- Luminescence Properties of Advanced Materials
- Magnetic properties of thin films
- Catalytic Processes in Materials Science
- Characterization and Applications of Magnetic Nanoparticles
- Pigment Synthesis and Properties
- X-ray Diffraction in Crystallography
- Clay minerals and soil interactions
- Chemical and Physical Properties in Aqueous Solutions
- Spectroscopy and Quantum Chemical Studies
- Mesoporous Materials and Catalysis
- Crystal Structures and Properties
- Nuclear materials and radiation effects
- Material Dynamics and Properties
- Industrial Gas Emission Control
- Nanoparticle-Based Drug Delivery
- Advanced materials and composites
- Phase-change materials and chalcogenides
- Multiferroics and related materials
- Gas Sensing Nanomaterials and Sensors
- Quantum Dots Synthesis And Properties
- Layered Double Hydroxides Synthesis and Applications
- Mineralogy and Gemology Studies
National Interuniversity Consortium of Materials Science and Technology
2008-2022
University of Cagliari
2013-2022
Istituto Nazionale di Fisica Nucleare, Sezione di Cagliari
2003-2020
Istituto Officina dei Materiali
2015
Institute of Structure of Matter
2008
Technical University of Denmark
2008
National Interuniversity Consortium for the Physical Sciences of Matter
2008
University of Milano-Bicocca
2008
Ca' Foscari University of Venice
2005
In-Q-Tel
2004
The possibility to finely control nanostructured cubic ferrites (MIIFe2O4) paves the way design materials with desired magnetic properties for specific applications. However, strict and complex interrelation among chemical composition, size, polydispersity, shape surface coating renders their correlation not trivial predict. In this context, work aims discuss heating abilities of Zn-substituted cobalt ferrite nanoparticles different zinc contents (ZnxCo1−xFe2O4 0 < x 0.6), specifically...
An Fe2O3−SiO2 composite was prepared by a gelation method that adopts tetraethoxysilane and iron(III) nitrate as starting materials. The dried gel treated at increasing temperatures, the samples were characterized XRD, TEM, magnetic susceptibility measurements, EPR Mössbauer spectroscopies. Nanometer size (3−4 nm) X-ray-amorphous oxide particles are observed in low temperature. These display superparamagnetic behavior spectra their moments indicate antiferromagnetic clustering. occurrence of...
The structure and the magnetic properties of a series Fe2O3−SiO2 nanocomposites (9−33 wt % Fe2O3), prepared by sol−gel method submitted to thermal treatments in temperature range 300−900 °C, were investigated through XRD, TEM, EPR, susceptibility measurements. Superparamagnetic iron(III) oxide nanoparticles with narrow size distribution, dispersed over amorphous silica matrix, are present all samples. They mostly amorphous, antiferromagnetic samples treated at low temperatures. At T > 700...
Molecular coating of nanoparticles represents probably the most important and, at same time, critical step to design new nanostructured magnetic materials. The interaction between molecules and surface atoms leads a strong modification properties, that are one key points in physics nanoparticles. In this paper properties CoFe2O4 (⟨D⟩ ≅ 4–8 nm) coated with oleic acid have been investigated order clarify role molecular on interparticle interactions anisotropy. An increase anisotropy (i.e.,...
Spherical nanoparticles of surfactant-coated CoFe2O4 (core) were prepared through thermal decomposition metal acetylacetonates in the presence a mixture oleic acid and oleylamine uniformly coated with silica shell by using tetraethylorthosilicate (TEOS) ammonia micellar solution (core/shell). Transmission electron microscopy (TEM) analysis core/shell evidenced high homogeneity coating process producing single narrow size distribution. The combined use spectroscopic studies (NMR FTIR) on core...
CoFe2O4 nanoparticles (〈DNPD〉 ∼ 6 nm), prepared by a thermal decomposition technique, have been investigated through the combined use of dc magnetization measurements, neutron diffraction, and 57Fe Mössbauer spectrometry under high applied magnetic field. Despite small particle size, value saturation at 300 K (Ms ≅ 70 A m2 kg−1) 5 100 are rather close to bulk values, making samples with this method attractive for biomedical applications. Neutron diffraction measurements indicate typical...
This paper focuses on the magnetic properties of CoFe2O4 nanoparticles, discussing influence nanoparticles arrangements obtained by different synthesis methods. Using high thermal decomposition (HTD) and direct micellar (DM) routes, three samples with equal primary particle size (∼5 nm) were prepared. The HTD method allows one to obtain highly crystalline coated oleic acid organized in a self-assembling arrangement (ACoFeHTD). DM results be appropriate prepare either irregular (IACoFeDM) or...
The magnetic properties of cobalt ferrite nanoparticles dispersed in a silica matrix samples with different concentrations (5 and 10 wt% CoFe2O 4) same particle size (3 nm) were studied by magnetization, DC AC susceptibility, Mossbauer spectroscopy measurements. results indicate that the particles are very weakly interacting. (saturation anisotropy constant, spin-canting) discussed relation to cation distribution.
The magnetic properties of cobalt ferrite-silica nanocomposites with different concentrations (15, 30, and 50 wt %) sizes (7, 16, 28 nm) ferrite particles have been studied by static magnetization measurements Mossbauer spectroscopy. results indicate a superparamagnetic behavior the nanoparticles, weak interactions slightly increasing content particle size. From high-field spectra at low temperatures, cationic distribution degree spin canting estimated both parameters are only dependent on...
A very fast self-combustion reaction was applied for the first time to synthesis of a series magnetic CoFe2O4−SiO2 nanocomposites in wide range compositions (from 5 50 wt % CoFe2O4). Combining gelation method that adopts metal nitrates, citric acid and tetraethoxysilane as precursors with controlled thermal treatments, variety samples properties finely modulated were obtained. Particle formation evolution structural temperature investigated by analysis, X-ray diffraction, transmission...
Among solution‐processed nanocrystals containing environmentally benign elements, bismuth sulfide (Bi 2 S 3 ) is a very promising n‐type semiconductor for solar energy conversion. Despite the prompt success in fabrication of optoelectronic devices deploying Bi nanocrystals, limited understanding electronic properties represents hurdle further materials developments. Here, two key science issues light‐energy conversion are addressed: bandgap tunability via quantum size effect, and...
An easy, low-cost, repeatable seed-mediated growth approach in solvothermal condition has been proposed to synthesize bimagnetic spinel ferrite core-shell heterostructures the 10-20 nm particle size range. Cobalt and manganese nanoparticles (CoFe2O4 MnFe2O4) have coated with isostructural ferrites like maghemite/magnetite, MnFe2O4, CoFe2O4 similar cell parameters create different heterostructures. The conventional study of structure, morphology, composition combined advanced techniques order...
Magnetic properties of iron oxide nanoparticles with spinel structure are strictly related to a complex interplay between cationic distribution and the presence non-collinear spin (spin canting ).
This paper aims to analyze the competition of single particle anisotropy and interparticle interactions in nanoparticle ensembles using a random model. The model is first applied ideal systems non-interacting strongly dipolar interacting maghemite nanoparticles. investigation then extended more complex pure cobalt ferrite CoFe2O4 (CFO) mixed cobalt-nickel (Co,Ni)Fe2O4 (CNFO) Both samples were synthetized by polyol process exhibit same size (DTEM ≈ 5 nm), but with different interaction...
The sol−gel synthesis of TiO2 from TiCl4 assisted by the triblock copolymer EO20−PO70−EO20 (EO = −CH2CH2O−, PO −CH2(CH3)CHO−) as templating agent was carried out systematically changing H2O:Ti (rw) and HCl:Ti (ra) molar ratios. Mesoporous nanocrystalline samples with well-defined controlled phase composition (anatase, rutile, mixed phase) were obtained after calcination at 400 °C characterized for morphology, particle size, shape using TEM, HRTEM, XRD, surface area measurements. role rw ra...
Nanoporous spherical assemblies of iso-oriented cobalt ferrite nanoparticles with a high surface area were prepared via normal micelles process. The magnetic coated silica layer through an inverse route. microstructure and morphology studied by X-ray diffraction, transmission electron microscopy N2-physisorption techniques. primary CoFe2O4 nanocrystalline particles (∼7 nm) assemble into nanoporous aggregates average size about 50−60 nm the coating process leads to core−shell nanostructures...
Magnetic interactions in silica coated spherical nanoporous assemblies of CoFe2O4 nanoparticles have been investigated by low temperature field dependent remanent magnetization (MDCD and MIRM) relaxation measurements. The synthesis procedure leads to the formation aggregates about 50–60 nm diameter composed hexagonal shaped nanocrystals with shared edges. negative deviation from non-interacting case Henkel plot indicates predominance dipole–dipole favouring demagnetized state, although...
The effect of interparticle interactions on the magnetic behavior cobalt ferrite nanoparticles was investigated in a CoFe2O4/SiO2 nanocomposite with 50 wt % phase. A sample pure prepared by same method also studied, as reference. Both samples show irreversible behavior, when DC magnetization, M(T), is observed zero field cooling−field cooling (ZFC−FC) measurements. For higher than 0.2 T, ZFC curves two maximum and corresponding temperature proportional to raised 2/3 power (Tmax ∝ H2/3). This...
This paper focuses on the study of magnetic properties 9 nm magnetite nanocrystals. XRD and TEM measurements indicate presence crystalline particles, with a fraction them only partially crystallized or highly defective. The analysis temperature dependence zero-field-cooled/field-cooled magnetization thermoremanent provides evidence existence three regimes: high regime (300–100 K), an intermediate (100–20 low (below 20 K). characteristics such regimes are discussed.
Novel MeO<italic>x</italic>/SBA-15 (Me = Zn, Fe) nanosorbents exhibiting an excellent and durable performance for the H<sub>2</sub>S removal from hot gas streams.