Browsing by Autor "M. Morocoima"

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    ESTUDIO ESTRUCTURAL Y DIAGRAMA DE FASES DEL SISTEMA DE ALEACIONES Cu2Zn1-zMnzSnSe4
    (2021) Manuel Antonio Villarreal Uzcátegui; Ekadink Moreno; Miguel Quintero; Eugenio Quintero; M. Morocoima; Gerzón E. Delgado; Jines E. Contreras; M. Chourio
    The structural study and phase diagram of the alloy system Cu2Zn1-zMnzSnSe4 are reported. Polycrystalline samples were synthesized using the direct fusion and annealing technique from the constituent elements. X-ray diffraction analysis indicates that system crystallizes in the tetragonal stannite structure with a possible I4 2m space group. From differential thermic analysis (DTA) experiment the phase diagram was constructed for alloy system, which suggests that the region between 600 and 700 °C is biphasic coexisting stannite and wurtz-stannite phases (+). The peritectic decomposition of the system   (L+ZnSe) in the region between z = 0 and z  0.80 occurs at  800 oC, for z > 0.80 the peritectic temperature decreases to 700 oC with z = 1.0. The transition of liquid L to (L+ZnSe) is given by the boundary line between 1075 oC with z = 0 and 770 oC with z  0.80. The region of the diagram below 600 oC corresponds to the appearance of the tetragonal stannite phase, as it indicated by the X-ray diffraction study at room temperature.
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    PROPIEDADES MAGNÉTICAS DEL SISTEMA DE ALEACIONES Cu 2 Cd 1−Z Mn Z SnSe 4 ( MAGNETIC PROPERTIES OF THE ALLOY SYSTEM Cu 2 Cd 1−z Mn z SnSe 4 )
    (2018) Ekadink Moreno; Miguel Quintero; M. Morocoima; A U Manuel Villarreal; Eugenio Quintero; P. Grima; R. Tovar; D. Caldera; Silvana Alvarez; P. Bocaranda
    En este trabajo se reportan las medidas de susceptibilidad magnetica c en funcion de la temperatura en el rango de 2-300 K de muestras policristalinas del sistema de aleaciones semiconductor magnetico Cu 2 Cd 1 − z Mn z SnSe 4 . La constante de Curie C aumenta linealmente con la concentracion z. La temperatura de Curie-Weiss q y la temperatura de Neel T N aumentan linealmente con la concentracion z, debido a un cambio de orden parcial a desorden total de los atomos de Mn 2+ en el sistema. En una primera aproximacion, se puede considerar que el sistema de aleaciones tiene un comportamiento tipico de vidrio de espin, lo que implica que los iones de Mn 2+ se encuentran de alguna manera desordenados en la red cationica del material. Measurements of magnetic susceptibility c as a function of temperature in the range 2-300 K on polycrystalline samples of Cu 2 Cd 1 − z Mn z SnSe 4 magnetic semiconductor alloy system are reported. The Curie constant C increase linearly with z. The Curie-Weiss temperature θ and Neel temperature T N increase linearly with z due to a partial order change to total disorder of the Mn +2 ions in the system. In a first approximation, it can be considered that this system has typical spin glass behavior (spin glass system), which means that ions Mn +2 are somewhat disorderly way cationic network of material.