J. Osorio

University of Antioquia | UdeA · Instituto de Física

An F-scan nonlinear spectrometer is used to measure the two-photon absorption coefficient for CH3NH3PbBr3 perovskite films from 690 to 995 nm. This spectrometer uses an electrically focused tunable lens and a tunable femtosecondpulse laser (Mai Tai-HP) with a resolution of 5 nm. Two-band models and saturation irradiance corrections are used to fit...

The main objective of this research study is to integrate the use of technological tools for experimental sciences (e.g. physics) in teacher training processes. A teaching proposal is built on the basis of the Vergnaud's Theory of Conceptual Fields, in which the data acquisition (DAQ) system is implemented in physics laboratory courses taken by the...

We study dynamic magnetic behavior in the vicinity of the dynamic phase transition (DPT) for a suitable series of samples that have different Curie temperatures TC, which thus enables us to experimentally explore the role of the reduced temperature T/TC in the DPT. For this purpose, we fabricate Co1−xRux epitaxial thin films with uniaxial in-plane...

Analysis of crime scenes involving single-fire-gun projectiles requires the determination of the direction of arrival of a projectile at the target and other factors to reconstruct events. The movement of a projectile can be analyzed by applying Euler’s equations to a solid symmetrical rigid body. The present work starts from a Newtonian reformulat...

The study of cultural heritage requires sophisticated equipment that does not alter or destroys the materials composing the objects under study. The main requirement about an artifact or an ancient work of art, for its restoration or conservation processes, is information about its constituting elements. Energy-dispersive X-ray fluorescence (EDXRF)...

The synthesis of silver nanoparticles (AgNPs) has been increasingly extended due to its potential applications in fields such as optics, environmental, catalysis, electronics and as an antibacterial agent. In this way it is necessary to develop methods framed in green chemistry to achieve greater stability over time of the AgNPs. The present work a...

In this study, magnetic nanoparticles of magnetite were prepared by an eco-friendly method using aqueous leaf extracts of Aloe vera and Kalanchoe daigremontiana . These vegetal extracts have suitable characteristics such as high availability, low cost, and serve as good colloidal stabilizers. Synthetized products were characterized by Transmission...

We have investigated the magnetic, structural and morphological properties of ferromagnetic phases of manganite La 1-x Sr x MnO 3 with x = 0.3 (LSMO-30) and x = 0.4 (LSMO-40) prepared by solid state reaction method, and then subjected to mechanical ball milling at different times of 3, 6 and 12 h. All of the samples were characterized by X-ray diff...

In this work we report on the magnetocaloric effect of La 2/3 Ca 1/3 MnO 3 (LCMO) and La 2/3 Ca 1/3 Mn 0.94 Cr 0.06 O 3 (LCMCrO) manganite thin films grown by DC magnetron sputtering on LaAlO 3 (100) substrates. X-ray diffraction shows that both doped and undoped films crystallize in the orthorhombic structure. Magnetic measurements show a decrease...

A high sensitivity Kerr magnetometer (Δ I/I = 1/30) is presented, making use of open source hardware and software. By making time resolved measurements (up to 0.15 s/cycle) the signal quality has been greatly improved up to an order of magnitude, enabling us to compare our measurements with commercial vibrating sample magnetometers. We also present...

In this paper two-photon absorption coefficient $\beta$ and nonlinear refractive index ${n}_{2}$ have been measured at 1064 nm for a new two-dimensional (CH3(CH2)2NH3)2(CH3NH3)2Pb3Br10 hybrid perovskite. The nonlinear optical properties were measured using transmission and reflection F-scan techniques. As a reference, a three-dimensional CH3NH3PbBr...

Silver nanoparticles (AgNPs) were synthesized by chemical reduction of Ag ⁺ ions (from silver nitrate AgNO 3 ), using aqueous or ethanolic Aloe vera extracts as reducing, stabilizing, and size control agent. The nanoparticles’ sizes were between 2 and 7 nm for ethanolic extract and between 3 and 14 nm for aqueous extract, as measured by High-Resolu...

In order to get homogeneous and high-quality perovskite CH3NH3PbI3 films, different growing methods have been developed, but most of them are unsuitable to scaling up. In this work, we studied in a systematic approach the influence of CH3NH3Cl (MACl) surface treatment in the acetonitrile (ACN) deposition route. This method does not require vacuum n...

The synthesis of nanomaterials is currently one of the most active in nanoscience branches; especially those help improve the human quality life. Silver nanoparticles (AgNPs) are an example of this as it is known to have inhibitory and bactericidal effects. In this work, we report the synthesis of silver nanoparticles by chemical reduction method o...

A proportional detector for gas flow was designed, which can be applied to analyze both, bulk and thin films samples, using the Conversion Electron Mössbauer Spectroscopy technique (CEMS). The prototype is a stainless steel cylindrical chamber with extrusions for the input and output gas flow, conductive strands and a sample holder which is bound t...

Este trabajo se enfocó en el estudio de la influencia del contenido de nitrógeno sobre la microestructura, composición química, propiedades mecánicas y tribológicas de los recubrimientos de TaN depositados sobre acero inoxidable 420 y silicio (100) mediante la pulverización catódica. Los recubrimientos se depositaron en una atmosfera de argón/ nitr...

In recent years, organo-lead-halide perovskites have emerged as promising new materials for photovoltaics, reaching high efficiencies. The excellent photoelectronic properties and easy solution processing makes the lead perovskite an ideal light harvesting material in a solar cell. In spite of these great advantages, there are concerns about the le...

In presence of a uniform gravitational field, Euler equations for a gyroscope can be written as a non-linear equation for the components of Riemann's stereographic projection of the symmetry axis over a horizontal plane. Under the approximation of nutations with low amplitude, the solution of this equation corresponds to the sum of two rotating vec...

This study focused on the study of the influence of nitrogen content on the microstructure, chemical composition, mechanical and tribological properties of TaN coatings deposited on 420 stainless steel and silicon samples (100) using the magnetron sputtering technique. For the deposition of the TaN coatings an argon/nitrogen atmosphere was used, va...

A proportional detector for gas flow was designed, which can be applied to analyze both, bulk and thin films samples, using the Conversion Electron Mössbauer Spectroscopy technique (CEMS). The prototype is a stainless steel cylindrical chamber with extrusions for the input and output gas flow, conductive strands and a sample holder which is bound t...

Mercury is one of the persistent pollutants in wastewater; it is becoming a severe environmental and public health problem, this is why nowadays its removal is an obligation. Iron oxide nanoparticles are receiving much attention due to their properties, such as: great biocompatibility, ease of separation, high relation of surface-area to volume, su...

A comparative study of Raman spectra at room temperature of La2/3Ca1/3MnO3 (LCMO) and La2/3Ca1/3Mn0.97Fe0.03O3 (LCMFO) thin films, grown on monocrystalline substrates LaAlO3, is presented. The films were grown with thickness between 30 and 130 nm under identical deposition conditions by DC magnetron sputtering system at high O2 pressure. In order t...

Se presentan los resultados del proyecto de investigación: “El papel de la actividad experimental en la enseñanza del electromagnetismo en la educación superior”. Su objetivo fue diseñar una propuesta de enseñanza del electromagnetismo, basada en la actividad experimental que contribuya con el proceso enseñanza y aprendizaje a nivel universitario....

The element-selective technique of X-ray magnetic circular dichroism (XMCD) has been used to study the magnetic properties of La2/3Ca1/3Mn0.97Fe0.03O3 (LCMFO) thin films. XMCD measurements below the ferromagnetic ordering temperature at the Mn and Fe absorption edges allow the determination of the contributions and relative orientations of the Mn a...

Appropriate conditions for SnO2 powder synthesis doped with iron to 10% by using sol-gel route are found. The powders obtained have been analyzed by means of analytic spectroscopic techniques: Raman, Mössbauer, diffuse reflectance, Fourier transform infrared, and X-ray diffraction. Sn0.9Fe0.1O2 thin films deposited by AC magnetron sputtering on sil...

This investigation presents the magnetic and structural properties of ferromagnetic manganite La0.7Sr0.3MnO3, (LSMO), subjected to ball milling processes. The LSMO powder sample was obtained by solid state reaction from high purity precursors. From X-ray diffraction (XRD), the sample showed the characteristic peaks of this phase. By means of thermo...

In this work we study the substrate influence in magnetic properties and the critical behavior of La2/3Ca1/3MnO3 thin films grown on single-crystal substrate of LaAlO3, SrTiO3 and NdGaO3, using a DC-magnetron sputtering system. All films were growth under the same conditions and with thicknesses close to 130nm. We made measures of magnetization as...

We have investigated the magnetic, structural and morphological properties of La0.6Sr0.4MnO3 (LSMO-40) manganite particles, synthesized by solid state reaction method. The resulting LSMO-40 powders were milled in air atmosphere during 3, 6 and 12 hours, by using a planetary ball milling. Samples obtained were characterized by X-ray diffraction, sca...

The structural, electronic, and magnetic properties of Zn0.95Co0.05O, Zn0.95Fe0.05O, and Zn0.90Fe0.05Co0.05O nanoparticles prepared by a sol-gel method are presented and discussed. X-ray diffraction and optical analysis indicated that high spin Co2+ ions substitute for the Zn2+ ions in tetrahedral sites. 57Fe Mössbauer spectroscopy showed the prese...

Multilayer coatings represent a promising class of protective coatings due to the improvement in tribological, mechanical, and anticorrosive properties conferred to the coated surfaces. This has motivated the research, development and implementation of these materials in many industrial applications; nowadays the requirements of the industry are no...

We report the growth of thin films of the cobaltite YBaCo4O7 + δ by means of the dc magnetron sputtering technique at high oxygen pressure onto r (1012) sapphire substrates. The films were characterized according to their structural, morphological, electrical, magnetic, and optical properties. An analysis of the X-ray diffraction pattern indicates...

Thin films of YBaCo4O7+δ were deposited on r (1012)-oriented Al2O3 substrates by dc magnetron sputtering. The as-grown films were characterized after their structural, morphological and optical properties. Special attention is devoted to the analysis of the optical response of these films as reports on optical properties of YBaCo4O7+δ, especially i...

We prepared Sn1−x Fe x O2 (x = 0, 0.03, 0.05, 0.10, and 1.0) nanoparticles by the polymeric precursor method based on the modified Pechini process. Two types of starting reactants for both tin and iron were explored: Sn(II)/Fe(II) and Sn(IV)/Fe(III) precursors. Thermogravimetric analysis revealed that the precursor powders prepared from Sn(IV) have...

Most of the hard coatings have good wear and corrosion resistance; they have been widely used commercially to increase the life span of some industrial elements, for example, cutting tools, sprockets, bearings and components for industrial machinery. In this work TiN/ZrN multilayer coatings were deposited with 10 bilayers by r.f. magnetron sputteri...

In the first stage of manufacture of artificial teeth, pigments are dispersed in a dry powder composed of fine spherical particles of acrylic resin. This dispersion has different characteristics to the usual dispersion of pigments in liquid resins of paints and coatings, or in the manufacture of plastics. There is a lack of reports on methods of an...

The injection molding process for polymer manufacturing requires mirror finish mould surfaces for the fabrication of a lot of products. A problem is the adherence of the injected products to the core, which negatively affects the product quality. This fact leads to expensive inserts mould fabrication, which can represent up to 20% of the productivi...

The present work is aimed to compare the physical properties of Sn1-x Fex O2-d\mbox{Sn}_{1-x} \mbox{Fe}_x \mbox{O}_{2-\delta } (x = 0, and 0.05) nanopowders obtained by sol–gel method, mechanochemical alloying, and mechanochemical alloying followed by thermal treatment. The X-ray diffraction of Sn1-x Fex O2-d\mbox{Sn}_{1-x} \mbox{Fe}_x \mbox{O}_{2-...

The injection molding process for polymer manufacturing requires mirror finish mould surfaces for the fabrication of a lot of products. A problem is the adherence of the injected products to the core, which negatively affects the product quality. This fact leads to expensive inserts mould fabrication, which can represent up to 20% of the productivi...

In this work we review the deduction of Fresnell coefficient for the reflexion of polarized light over a magnetized medium. We obtained the expressions for the Kerr angle in both polar and equatorial case. It is shown that the effect polar magneto–optic effect is two order stronger than the equatorial. This treatment is only valid for magnetic fiel...

In this work we review the deduction of Fresnell coefficient for the reflexion of polarized light over a magnetized medium. We obtained the expressions for the Kerr angle in both polar and equatorial case. It is shown that the effect polar magneto-optic effect is two order stronger than the equatorial. This treatment is only valid for magnetic fiel...

The effect of different milling conditions on the formation of Fe-doped TiO2 powders by mechanical alloying was investigated by Mössbauer spectrometry. The milling conditions investigated were ball to powder weight ratio, milling time, rotation velocity of supporting disc, and the type of starting reactive iron and its concentration. X-ray diffract...

Fe-doped TiO2 powders were obtained by mechanical alloying. The starting materials were anatase TiO 2 and metallic iron (α-Fe). The influence of different milling conditions such as: ball to powder weight ratio (20:1, 40:1); milling time (6, 12, 18 and 24 hours); rotation velocity of supporting disc (250 and 390 rpm) and dopant concentration ( 1, 4...

We have grown hematite (αα-Fe2O3) thin films on stainless steel substrates and magnetite (Fe3O4) thin films on (0 0 1)-Si single crystal substrates by a RF magnetron sputtering process. αα-Fe2O3 thin films were grown in an Ar atmosphere at substrate temperatures around 400∘C, and Fe3O4 thin films in an Ar/O2 reactive atmosphere at substrate tempera...

Fe-doped TiO2 powders were obtained by mechanical alloying. The starting materials were anatase TiO2 and metallic iron (α-Fe) or hematite (α-Fe2O3). The influence of different milling conditions such as: ball to powder weight ratio, milling time, rotation velocity of supporting disc, and dopant concentration on the structural and magnetic propertie...

In this work, iron-doped SnO2 powders were prepared by two methods: mechanical alloying and mechanochemical alloying with successive thermal treatment. The influence of different milling conditions such as ball to powder weight ratio, milling time, rotation velocity of supporting disc and the type of iron starting reactive and their Fe concentratio...

The present work is aimed to investigate experimental conditions to obtain pure Sn1-xFexO2-delta (x=0, 0.05, and 0.1) powders by three methods: (1) sol-gel method, (2) mechanochemical alloying and (3) thermal treatment. In (1), different precursors were employed: mixtures of Sn^4+ and Fe^3+ or Sn^2+ and Fe^2+. In (2), SnO2 and alpha-Fe or alpha-Fe2...

We have grown hematite (alpha-Fe2O3) thin films on stainless steel and silicon dioxide (SiO2) substrates and magnetite (Fe3O4) thin films on silicon substrates by RF magnetron sputtering process. Conversion Electron Mössbauer (CEM) spectra of these films exhibit hyperfine parameter values which are characteristic of these iron oxides. Magnetization...

In this work we present the analysis of effect of the oxygen pression in the growth process of La2/3Ca1/3MnO3 (LCMO) thin films, using by electrical resistance measurements as a function of temperature between 180 and 295K. The analysis were made on several LCMO films growth on monocrystal substrate of LaAlO3, using by an sputtering system with DC...

We have grown hematite (α − Fe 2O 3) thin films on stainless steel and (001)-silicon single-crystal substrates by RF magnetron sputtering process in argon atmosphere at substrate temperatures from 400 to 800°C. Conversion Electron Mössbauer (CEM) spectra of the sample grown on stainless steel at 400°C exhibit values for hyperfine parameter characte...

We have derived the Melchers¿ mathematical model of the oxygen diffusion across the rust layer formed on the surface of the steels submitted to total immersion, by a most fundamental principle: the Planck-Nersnt law. To achieve it, we have neglected the convection and migration of the oxygen molecules, and we have assumed both that this problem is...

Tunneling measurements at different temperatures were carried out in SrRuO3/Pb(Zr0.52Ti0.48)O3/Pt capacitor structures grown on (100) SrTiO3 single-crystal substrates using a high-oxygen pressure on axis sputtering technique. Crystalline quality and structure were measured by X-ray diffractometry (XRD). The surface roughness and morphology were stu...

Tunneling measurements at different temperatures were carried out in SrRuO3/Pb(Zr0.52Ti0.48)O3/Pt capacitor structures grown on (100) SrTiO3 single-crystal substrates using a high-oxygen pressure on axis sputtering technique. Crystalline quality and structure were measured by X-ray diffractometry (XRD). The surface roughness and morphology were stu...

We have grown YBa ₂ Cu ₃ O _7-δ (40  nm )/ La _1/3 Ca _2/3 MnO ₃ (2  nm )/ La _2/3 Ca _1/3 MnO ₃ (30  nm ) junctions for quasiparticle-injection measurements. Ferromagnetic (F), antiferromagnetic (AF), and superconducting (S) thin films were sequentially g...

We investigate the magnetic properties of 200-nm thick La0.67Ca0.33MnO3 films, which were grown under identical conditions onto five single crystal substrates: SrTiO3(001), LaAlO3(001), MgO(001), NdGaO3(001) and Si(111). The films exhibit a strong substrate dependence of the magnetic properties, including the coercive field, remanent magnetization...

Using a dc sputtering method at hi gh oxygen pressures we have deposited YBa 2 Cu 3 O 7-x (YBCO) and YBCO+5% Ag thin films, with different oxygen content, on SrTiO 3 (100). These films were illuminated with 632.8 nm laser light, at room temperature. The change of the electrical resistance caused by illumination indicates the presence of two effects...

An in situ deposition sputtering process at high pressure has been developed for preparing high quality superconducting Bi2Sr2CaCu2O8+δ thin films on different substrates. Both microstructural and electrical properties were well characterized by TEM, AFM, RBS, X-ray diffraction, resistivity and magnetic susceptibility. The high reproducibility of t...

Fully oxygenated epitaxial thin films of YBa2Cu3O7-δ with thicknesses between 100 and 300 nm were deposited by a dc high oxygen pressure sputtering method on (001) SrTiO3 substrates. From these films we have obtained samples with different oxygen deficiency x between 0.2 to 0.8, using a thermal treatment. These films were illuminated at 10K, 95K, 2...

Highly conductive SrRuO3 (SRO) oxide thin films have been grown "in situ" on (001) SrTiO3 by using a DC sputtering technique at high oxygen pressures (3.5 mbar). SRO thin films grew highly (001)-oriented for substrate temperatures above 600 ^oC. AFM analysis showed surface roughness of about 3.6 nm for SRO-film thickness of 100 nm. The samples have...

Se realizó un montaje de Efecto Kerr Magneto-Óptico (MOKE) para realizar medidas de magnetización en función de un campo magnético aplicado. Este montaje se realizó en una mesa antivibratoria usando un láser de He-Ne de 25 mW polarizado linealmente, dos sensores de luz, un electroimán con su respectiva fuente de corriente, un gaussímetro, un microv...