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dc.contributor.advisorCastellano-Rodríguez, Dorial
dc.contributor.authorOrtiz-Andrade, Gina L.
dc.date.accessioned2019-04-15T17:19:24Z
dc.date.available2019-04-15T17:19:24Z
dc.date.issued2005
dc.identifier.urihttps://hdl.handle.net/handle/20.500.11801/2088
dc.description.abstractIn this thesis we studied the thermal properties, such as specific heat, thermal conductivity, and heat flow, as function of the temperature for crystals of the A2BX4 type, specifically: Cs2ZnI4, {N(CH3)4}2CoCl4 , and Cs2CoCl4. These crystals were grown by slow evaporation and fast evaporation methods and the properties were measured by the thermoelectric chamber method realized by the research group of Dr. Dorial Castellanos and the Differential Scanning Calorimeter DSC 2920. In this way we verified the effectivity of our technique in comparison with the results of other authors, other methods, and different instruments [1,2,3,4,5,6,7,8,9]. Graphs of specific heat, thermal conductivity and heat flow as function of the temperature were constructed. It was found that these crystals go through a series of phase transitions. For the crystal Cs2ZnI4 these transitions occurred in the range of temperatures between -10 and 0 ◦C associated with a transition of structural type related to incommensurability and between 37 and 45 ◦C associated to the Jahn-Teller effect. For the crystal {N(CH3)4}2CoCl4 these transitions occurred between -15 and 21 ◦C for the structural type and between 28.3 and 33.5 ◦C associated to the Jahn-Teller effect. For the crystal Cs2CoCl4 it was found that at temperatures between 52 and 56.4 ◦C there is a non structural phase transition associated with the Jahn-Teller effect of which some features can be appreciated at temperatures as low as 18.9 ◦C.en_US
dc.description.abstractEn este trabajo se realizó el estudio de las propiedades térmicas tales como calor especifico, conductividad térmica y flujo de calor en función de la temperatura en cristales de tipo A2BX4, específicamente: Cs2ZnI4, {N(CH3)4}2CoCl4 , y Cs2CoCl4. Los mismos fueron crecidos por el método de evaporación lenta y rápida y se midieron dichas propiedades usando el método de la cámara termoeléctrica realizada por el grupo de investigación del Dr. Dorial Castellanos y el equipo Differential Scanning Calorimeter DSC 2920. De este modo se verifica la efectividad de nuestra técnica al comparar nuestros resultados con los de otros autores, otros métodos y diferentes equipos[1,2,3,4,5,6,7,8,9]. Se construyeron gráficas de calor específico, conductividad térmica y flujo de calor en función de la temperatura en los cuales se encontró como estos cristales pasan por una serie de transiciones de fase. Para el cristal Cs2ZnI4 estas transiciones ocurren a un rango de temperaturas críticas entre -10 y 0 ◦C relacionada a una transición de fase estructural de tipo inconmensurable y entre 37 y 45◦C asociadas al efecto Jahn - Teller. Para el cristal {N(CH3)4}2CoCl4 estas transiciones ocurren entre -15 y 21◦C para la de tipo estructural y entre 28.3 y 33.5◦C para la asociada al efecto Jahn -Teller y para el cristal Cs2CoCl4 se encontró que a temperaturas entre 52 y 56.4◦C están relacionados con la transición de fase de tipo no estructural asociada al efecto Jahn - Teller de la cual se pueden apreciar algunos rasgos a temperaturas tan bajas como de 18.9◦C.en_US
dc.language.isoEspañolen_US
dc.titleCrecimiento y medidas de las propiedades térmicas en cristales Cs2ZnI4, {N(CH3)4}2CoCl4, y Cs2CoCl4en_US
dc.typeThesisen_US
dc.rights.licenseAll rights reserveden_US
dc.rights.holder(c) 2005 Gina Liliana Ortiz-Andradeen_US
dc.contributor.committeeQuiñones, Luis M.
dc.contributor.committeeVelázquez Esov
dc.contributor.representativeSchellekens, Johannes H.
thesis.degree.levelM.S.en_US
thesis.degree.disciplinePhysicsen_US
dc.contributor.collegeCollege of Arts and Science - Scienceen_US
dc.contributor.departmentDepartment of Physicsen_US
dc.description.graduationYear2005en_US


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