A5043535307- ZnO doping and properties
- Magnetic Properties and Synthesis of Ferrites
- Magnetic Properties of Alloys
- Magnetic and transport properties of perovskites and related materials
- Iron oxide chemistry and applications
- Advanced Condensed Matter Physics
- Magnetic properties of thin films
- Rare-earth and actinide compounds
- Electronic and Structural Properties of Oxides
- Multiferroics and related materials
- Copper-based nanomaterials and applications
- Gas Sensing Nanomaterials and Sensors
- Metallic Glasses and Amorphous Alloys
- X-ray Diffraction in Crystallography
- Hydrogen Storage and Materials
- Catalytic Processes in Materials Science
- Microstructure and Mechanical Properties of Steels
- Crystallization and Solubility Studies
- Magnetic Properties and Applications
- Transition Metal Oxide Nanomaterials
- Magneto-Optical Properties and Applications
- Conducting polymers and applications
- Superconducting Materials and Applications
- Thermal and Kinetic Analysis
- Biosensors and Analytical Detection
Universidad Nacional de La Plata
2013-2024
Instituto de Física La Plata
2011-2024
Consejo Nacional de Investigaciones Científicas y Técnicas
2013-2024
Universidade Federal de Alfenas
2016
Universidad de Sevilla
1977
In recent years there has been an intense search for room temperature ferromagnetism in doped dilute semiconductors, which have many potentially applications spintronics and optoelectronics. We report here the unexpected observation of significant a semiconductor with nonmagnetic impurities, Cu-doped TiO$_2$ thin films grown by Pulsed Laser Deposition. The magnetic moment, calculated from magnetization curves, resulted surprisingly large, about 1.5 $\mu_B$ per Cu atom. A large moment was...
This work probes the relevance of oxygen vacancies in formation local ferromagnetic coupling between Fe ions at octahedral sites zinc ferrites. gives rise to a ferrimagnetic ordering with Curie temperatures above room temperature an otherwise antiferromagnetic compound. conclusion is based on experimental results from x-ray magnetic circular dichroism measurements $\mathrm{Fe}{\mathrm{L}}_{2,3}$ edges and magnetization performed ferrites, nanoparticles, films, different cation distributions...
We present an investigation of Fe-doped TiO2 anatase nanoparticles (2.8 and 5.4 at.% Fe) where Fe substitutes Ti atoms without the presence other phases. In order to characterize these samples we used x-ray absorption experiments, 57Fe Mössbauer spectroscopy, ab initio calculations magnetometry. Results from iron K-edge near-edge extended fine structure confirm that Fe3+ replaces Ti4+ in increasing metal-anion bond length. spectra recorded at room temperature show asymmetric broad doublets....
X-ray absorption near-edge and grazing incidence x-ray fluorescence spectroscopy are employed to investigate the electronic structure of ZnFe${}_{2}$O${}_{4}$ thin films. The techniques used determine nonequilibrium cation site occupancy as a function depth oxygen pressure during deposition its effects on magnetic properties. It is found that low pressures below 10${}^{\ensuremath{-}3}$ mbar cause iron superoccupation tetrahedral sites without Zn${}^{2+}$ inversion, resulting in an ordered...
Roasted and ground coffee is targeted by fraudulent addiction of products.In this way the determination contaminants in has economic nutritional importance.In study, adulteration corn were detected using DSC (differential scanning calorimetry) FTIR (Fourier transform infrared spectroscopy) coupled to PCA (principal component analysis), PLS (partial least squares) models.Three different levels roasted Coffea arabica L. used prepare mixtures with corn.The level was between 0.5 40% (m/m).It...
We report the existence of magnetic order at room temperature in Li-doped ZnO microwires after low energy H+ implantation. The with diameters between 0.3 and 10 μm were prepared by a carbothermal process. combine spectroscopy techniques to elucidate influence electronic structure local environment Zn, O, Li their vacancies on response. Ferromagnetism is obtained only implanting ZnO. overall results indicate that low-energy proton implantation an effective method produce necessary amount...
Molecular diagnostic methods to detect and quantify viral RNA in clinical samples rely on the purification of genetic material prior reverse transcription polymerase chain reaction (qRT-PCR). Due large number processed laboratories, automation has become a necessity order increase method processivity maximize throughput per unit time. An attractive option for isolating is based magnetic solid phase separation procedure (MSPS) using microparticles. This offers advantage over other alternative...
In this work, we present an experimental and theoretical study of structural magnetic properties Fe doped rutile TiO2 nanopowders. We show that Fe-doping induces the formation oxygen vacancies in first-sphere coordination iron ions, which are +2 +3 oxidation states. found ions form dimers share one vacancy case Fe3+ two Fe2+. The saturation magnetization is almost independent concentration slightly increases with relative fraction Ab initio calculations sharing coupled ferromagnetically,...
Commercial LaAlO3 substrates were thermally cycled simulating a procedure similar to those followed during TiO2 and SnO2 dilute magnetic semiconductors’ film pulsed laser deposition. Ferromagneticlike behavior was found in some substrates, which metallic iron impurities detected by x-ray photoelectron spectroscopy total reflection fluorescence measurements. A thorough experimental investigation, using high resolution techniques, showed that these introduced the used fix oven silicon holders....
We present here an ab initio study of the structural, magnetic, and hyperfine properties Fe-doped rutile SnO2 for different concentrations distributions Fe atoms oxygen vacancies in host. The calculated results are compared with experimental ones obtained by Mössbauer spectroscopy X-ray absorption techniques. This comparison enables us to characterize local structure around identify interactions that observed samples prepared methods. It is concluded fundamental ferromagnetic response SnO2....
In this work, we report direct evidence of ferromagnetism in hydrogenated ZnO sub-micrometric powders. Hydrogen (H2) was incorporated under a high-pressure heat treatment sealed reactor. Ferromagnetism at room temperature can be activated and deactivated by annealing H2 air atmospheres, respectively. incorporation structure observed from X-ray absorption near-edge spectra where hydrogen acts as shallow donor transferring electrons to the conduction band (Zn 4s). The Raman measurements clear...
Nanostructured MFe 2 O 4 act as catalysts in the decomposition of ammoniun nitrate The addition reduces onset temperature exothermic reaction NH NO 3 . metal cations ferrites acidic Lewis sites removing ammonia. catalytic performance is associated with electronegativity M 2+ cations. best achieved CoFe Effect nanostructured (M= Cu, Co, Mg, Zn) on thermal ammonium
In this work we present a combined theoretical and experimental study of the structural, magnetic, hyperfine properties Fe doped (Fe, Sn) co-doped SrTiO3 perovskite (STO). 57Fe-Mössbauer spectroscopy (57Fe-MS) was employed to determine interactions at sites STO for different Sn concentrations. The performed in framework Density Functional Theory (DFT) using full-potential linearized augmented plane wave (FP-LAPW) method. effect oxygen vacancies on magnetic alignment impurities studied....