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5 results on '"Marisa Alejandra Frechero"'

1. Anion-cation dynamic cooperation in a paradigmatic ionic conductor around its superionic transition

Author

Marisa Alejandra Frechero, Eider Iván Vivas Tulandy, and Alvaro Garcia Muriel

Subjects
Statistics and Probability, Work (thermodynamics), Materials science, HOPPING MECHANISM, Ciencias Físicas, Silver iodide, Ionic bonding, Condensed Matter Physics, 01 natural sciences, MOLECULAR DYNAMIC, 010305 fluids & plasmas, Ion, Conductor, Molecular dynamics, chemistry.chemical_compound, SOLID IONIC CONDUCTOR, chemistry, Chemical physics, 0103 physical sciences, Fast ion conductor, 010306 general physics, Pair potential, CIENCIAS NATURALES Y EXACTAS, Física de los Materiales Condensados
Abstract

Silver iodide (AgI) is one of the most extensively studied superionic conductors. In this work, we have applied the standard Buckingham pair potential and standard charge. For the first time the microscopic dynamic events that allow the achievement of the superionic transition are revealed. A collaborative effect among cations and anions that makes possible the hopping mechanism within the appropriate timescale is revealed. Fil: Tulandy, Eider Iván Vivas. Universidad Politécnica de Cartagena; España Fil: García Muriel, Alvaro. Universidad de Cartagena; Colombia Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

Published
2019

2. Sol-gel synthesis and electrical characterization of doped-carbon decorated mixed conductor ceramics

Author

M.A. de la Rubia, S. Terny, Marisa Alejandra Frechero, J. Vega-Castillo, and J. de Frutos

Subjects
Materials science, Físico-Química, Ciencia de los Polímeros, Electroquímica, Niobium, chemistry.chemical_element, Vanadium, 02 engineering and technology, Conductivity, 010402 general chemistry, 01 natural sciences, General Materials Science, Ceramic, Electrical conductor, Mechanical Engineering, Ciencias Químicas, MIXED CONDUCTOR CERAMIC, IMPEDANCE SPECTROSCOPY, Carbon black, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Copper, 0104 chemical sciences, chemistry, Chemical engineering, Mechanics of Materials, visual_art, visual_art.visual_art_medium, SOL-GEL METHOD, 0210 nano-technology, Carbon, CIENCIAS NATURALES Y EXACTAS
Abstract

New mixed composite conductors of compositions: Li3V2−x [Cu]x (PO4)3/C and Li3V2−x [Nb]x(PO4)3/C (x = 0.1; 0.2 and 0.3) have been synthesized by the sol-gel method using Citric and Oxalic acids as a primary carbon source and Carbon Black or Carbon Nano-Fibers as secondary carbon sources. The combination of these carbon forms with the Nb doped-polyanion material boosts their electrical behavior up to 10−3 S.m−1 that is two orders of magnitude higher than the Li3V2(PO4)3/C at a room temperature. SEM, TEM and Micro-Raman Spectroscopy evidence that Carbon Nano-Fiber blend is better conductor than Carbon Black blend, which is also revealed by complex conductivity spectra. The conductivity behavior of Nb-doped ceramic is better than the Cudoped one. The obtained niobium composites have a much more stable structure compared to the copper ones because the niobium atoms fit well in the vanadium position, whereas copper atoms are expelled from the structured. Fil: Terny, Cintia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Vega Castillo, Jesus Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentina Fil: de la Rubia, María Ángeles. Centro de Materiales y Dispositivos Avanzados para TIC. Grupo de Propiedades Ópticas, Eléctricas y Magnéticas de Materiales y sus Aplicaciones.; España Fil: de Frutos, José. Centro de Materiales y Dispositivos Avanzados para TIC. Grupo de Propiedades Ópticas, Eléctricas y Magnéticas de Materiales y sus Aplicaciones.; España Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

Published
2019

3. Is ergodicity in an oxide glass ionic conductor a matter of time?

Author

Marisa Alejandra Frechero, Cristian Balbuena, and R.A. Montani

Subjects
Statistics and Probability, Work (thermodynamics), Lithium metasilicate, Materials science, Condensed matter physics, Transition temperature, Ciencias Físicas, Ergodicity, Ionic bonding, Statistical mechanics, Condensed Matter Physics, chemistry.chemical_compound, Molecular dynamics, MOLECULAR DYNAMIC SIMULATION, chemistry, LITHIUM METASILICATE GLASS, GLASS TRANSITION TEMPERATURE, Glass transition, CIENCIAS NATURALES Y EXACTAS, BROKEN ERGODICITY PHENOMENA, Física de los Materiales Condensados
Abstract

From the results of molecular dynamic simulations of lithium metasilicate glass - at temperatures above and below their transition temperature (Tg ) - we propose a simple graphical representation to search for the broken ergodicity in an ionic oxide glass. Knowing whenergodicity is lost is critical for the proper use of statistical mechanics as a tool for measuring dynamical and structural properties through molecular dynamic simulation. This work shows how an abrupt qualitative transformation occurs in the way the system explores itspossible states when it goes down below the glass transition temperature range. We revise the broken ergodicity phenomena through its relationship with the observation time and the dynamic diversity of their atoms. Fil: Balbuena, Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Montani, Ruben Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; Argentina

Published
2015

4. Electrical response of bivalent modifier cations into a vanadium-tellurite glassy matrix

Author

E.C. Cardillo, Marcelo A. Villar, P.E. diPrátula, C.S. Terny, and Marisa Alejandra Frechero

Subjects
Tellurite glasses, Materials science, Barium oxide, Otras Ciencias Químicas, Inorganic chemistry, Ciencias Químicas, Ionic bonding, Vanadium, chemistry.chemical_element, Impedance spectroscopy, Barium, Condensed Matter Physics, Polaron, Electronic, Optical and Magnetic Materials, Dielectric spectroscopy, chemistry.chemical_compound, Oxide glasses, Transition metal, chemistry, Ionic conductivity, Materials Chemistry, Ceramics and Composites, CIENCIAS NATURALES Y EXACTAS
Abstract

In this work, we suggest an explanation of the electrical conductivity behavior of tellurite glassy systems modified with barium when transition metal oxides (V2O5-MoO3) present in the glassy matrix are replaced progressively by barium oxide. These glasses of formula x BaO (1 − x)(0.5 V2O5· 0.5 MoO3)2 TeO2 are obtained by the standard quenching technique and analyzed by means of impedance spectroscopy. We also report some structural results that explain the effect of the bivalent cation (Ba+2) on the electrical response in comparison to the effect of univalent cations on this kind of glassy matrix. The results confirm the existence of a transition from a typical hopping of small polarons response (when the content of BaO is low) to a weak ionic conductive response (when more than 50% of the transition metal oxides content has been replaced by BaO). The independent migration path is suggested by the observed electrical conductivity behavior. In this system, vanadium gives the active centers responsible for the polaron hopping mechanism while barium cations seem to be responsible for the ionic transport regimen. Fil: Terny, Cintia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Cardillo, Evangelina Cinthia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Di Pratula, Pablo Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Villar, Marcelo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Planta Piloto de Ingeniería Química (I). Grupo Vinculado al Plapiqui - Investigación y Desarrollo en Tecnología Química; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

Published
2014

5. A weak mixed mobile ion effect in vanadium-tellurite oxide glass modified by silver and lithium cations

Author

R.A. Montani, Marisa Alejandra Frechero, and E.C. Cardillo

Subjects
TELLURITE GLASSES, Inorganic chemistry, Otras Ciencias Naturales y Exactas, Oxide, chemistry.chemical_element, Vanadium, IMPEDANCE SPECTROSCOPY, Condensed Matter Physics, Vanadium oxide, Electronic, Optical and Magnetic Materials, Dielectric spectroscopy, chemistry.chemical_compound, chemistry, Materials Chemistry, Ceramics and Composites, Ionic conductivity, Lithium, Lithium oxide, IONIC CONDUCTIVITY, Silver oxide, CIENCIAS NATURALES Y EXACTAS
Abstract

The effect of the partial replacement of lithium oxide by silver oxide in a glassy vanadium-molybdenum-tellurite oxides matrix is analyzed by means of impedance spectroscopy. We find that a weak mixed mobile ion effect (MMIE) is due to the different kind of modifications silver and lithium oxides induce in the glass of formula 0.7[x Ag2O (1 - x) Li2O] 0.3[0.5 V2O5 0.5 MoO3] 2 TeO2. Fil: Cardillo, Evangelina Cinthia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Montani, Ruben Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina Fil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentina

Published
2010

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