Browsing by Autor "M. Quintero"

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Crystal structure of the quaternary compounds CuFe2AlSe4 and CuFe2GaSe4 from X-ray powder diffraction
(Springer Science+Business Media, 2015) Gerzón E. Delgado; Asiloé J. Mora; P. Grima; M.A. Morris; S. Durán; M. Quintero; J.M. Briceño
Panlar Recommendations for the Management of Knee Osteoarthritis
(Elsevier BV, 2017) M. Quintero; R. Espinosa; H. Sánchez Riera; Raul Souto; Juan Diego Zamora Salas; Francisco Radrigán; Miguel Vera; J Bolaños; Lorena Urioste; Isa Iraheta
PHASE DIAGRAM OF (CuInTe 2 ) 1-x (FeTe) x ALLOYS (0 ≤ x ≤ 0.6) ( DIAGRAMA DE FASES DEL SISTEMA DE ALEACIONES (CuInTe 2 ) 1-x (FeTe) x (0 ≤ x ≤ 0.6)
(2017) P. Grima; M. Quintero; Luis Nieves; Humberto Cabrera; Eduardo Pérez Cappe; Inti Zumeta‐Dubé; Jennifer A. Aitken; Jacilynn A. Brant
Polycrystalline samples of the (CuInTe2)1-x (FeTe)x alloy system where prepared by the melt and anneal technique and the products characterized by X-Ray Diffraction (XRD), Differential Thermal Analysis (DTA) and Optical Diffuse Reflectance Spectroscopy (ODRS) techniques. A first sight, samples were composed by a tetragonal phase with traces of a secondary phase identified as Fe1.125Te. Under exhaustive examination, it was found that the tetragonal phase, at the same time, is composed by two phases, with the same crystal structure and close lattice parameters, typical of spinodal decomposition. From ODRS measurements, optical absorption vs energy curves was obtained. These curves show how the addition of Fe produces a disordering-reordering process in the cationic sublattice suggesting that composition x=0.5 (CuFeInTe3) could be an intermediate compound in the diagram. Using the obtained information, a preliminary T-x phase diagram is proposed. Se prepararon muestras policristalinas del sistema de aleaciones (CuInTe2)1-x (FeTe)x por la tecnica de fusion y recocido; los productos fueron caracterizados por las tecnicas de Difraccion de Rayos X (DRX), Analisis Termico Diferencial (ATD) y Reflectancia por Espectroscopia de Optica Difusa (REOD). A primera vista, las muestras se componen de una fase tetragonal con trazas de una fase secundaria identificada como Fe1.125Te. Bajo un examen mas exhaustivo, se encontro que la fase tetragonal se compone a su vez de dos fases, con la misma estructura cristalina y parametros de red cercanos, tipico de una descomposicion espinodal. A partir de mediciones REOD, se obtuvieron las curvas de absorcion optica vs energia. Estas curvas muestran como la adicion de Fe produce un proceso de desorden-reorden en la subred cationica que sugiere que la composicion x = 0,5 (CuFeInTe3) podria ser un compuesto intermediario en el diagrama. Con la informacion obtenida, se propone un diagrama de fases T-x.
STRUCTURAL CHARACTERIZATION OF THE NEW DIAMOND-LIKE SEMICONDUCTOR CuNbGaSe3
(2018) Jesús Alberto Flores Cruz; Gerzón E. Delgado; Jines E. Contreras; M. Quintero; Luis Nieves; P. Grima
The chalcogenide compound CuNbGaSe3, belonging to the system I-II-III-VI3, has been investigated by means of X-ray powder diffraction and its crystal structure has been refined by the Rietveld method.This is a material of the semiconductor type, which improves the properties of a simple semiconductor like CuGaSe2 because it ads spintronic applications due to its magnetic behavior. The powder pattern was composed by 94.2% of the principal phase CuNbGaSe3 and 5.8% of the secondary phase Cu0.667NbSe2. This material crystallizes with a CuFeInSe3-type structure in the tetragonal space group P4 2c (Nº 112), unit cell parameters a = 5.6199(4) Å, c = 11.0275(2) Å, V = 348.28(4) Å3, with a normal adamantane-structure where occurs a degradation of symmetry from the chalcopyrite structure I4 2d to a related structure P4 2c.