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Investigation of the incommensurate (INC) phase between α and β phases in quartz and related materials
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Date
2021-2-10
Author
Ateş, Simge
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Incommensurate (INC) phase as an intermediate sinusoidal phase which exists in anarrow temperature range (∼1.3◦C) between the low-temperatureαand the high-temperatureβphases in quartz, is investigated extensively. The phase transitions oftheα-INC and INC-βoccurring as first order and second order type, respectively,are studied using the experimental data from the literature. Order-disorder transi-tion between theαandβquartz through the incommensurate phase is described bytemperature and pressure dependence of the experimentally measurable macroscopicparameters in relation to the microscopic order parameter according to various mod-els, mainly the Landau phenomenological model.Our methods in this study form a guide to investigate crystals with similar phasediagram with quartz as tridymite and cristobalite, and incommensurate phases in someother materials with similar crystal structure to quartz such asNaNO2,K2SeO4andAlPO4.
Subject Keywords
Landau model
,
Phase transitions
,
Incommensurate phase
,
Quartz
URI
https://hdl.handle.net/11511/89831
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Graduate School of Natural and Applied Sciences, Thesis
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S. Ateş, “Investigation of the incommensurate (INC) phase between α and β phases in quartz and related materials,” Ph.D. - Doctoral Program, Middle East Technical University, 2021.
