First order and second order phase transitions in quartz and related materials

Download
2017
Lider, Mustafa Cem
The mechanism of the phase transitions in quartz and in the related materials is investigated. First order and second order transitions are explained on the basis of various models using experimental data from literature. Inparticular, the Landau phenomenological theory is employed in terms of the order parameters and the temperature- pressure (T-P) phase diagram is constructed for those materials of interest. The sym- metry change of crystal structure is also analyzed by using group theory. The thermodynamic quantities of quartz are obtained by calculating the order parameters using the experimental data from the literature. The calculated results are then interpreted with the ones stated in previous experimental studies.

Suggestions

Time-resolved optically stimulated luminescence (osl) studies on samples containing quartz and feldspar
Yeltik, Aydan; Bulur, Enver; Department of Physics (2009)
Time Resolved OSL (TR-OSL) is a technique to record the luminescence decay curve data after a brief stimulation pulse and can possibly be used for the separation of luminescence signals from quartz and feldspars. In this study luminescence emission from quartz and feldspar samples was investigated. TR-OSL signals of these samples were studied for the variations with preheating and annealing temperature, stimulation pulse width and total stimulation time, optical bleaching, radiation dose and measurement tem...
Dispersive optical constants of Tl2InGaSe4 single crystals
Qasrawi, A. F.; Hasanlı, Nızamı (IOP Publishing, 2007-09-01)
The structural and optical properties of Bridgman method grown Tl2InGaSe4 crystals have been investigated by means of room temperature x-ray diffraction, and transmittance and reflectance spectral analysis, respectively. The x-ray diffraction technique has shown that Tl2InGaSe4 is a single phase crystal of a monoclinic unit cell that exhibits the lattice parameters of a = 0.77244 nm, b = 0.64945 nm, c = 0.92205 nm and beta = 95.03 degrees . The optical data have revealed an indirect allowed transition band ...
Magnetic monitoring approach to kinetics of phase transformations in multicomponent alloy systems
Duman, Nagehan; Mekhrabov, O. Mekhrabov; Akdeniz, Mahmut Vedat; Department of Metallurgical and Materials Engineering (2012)
It is of great importance for a materials scientist both from fundamental and applicability aspects to have better understanding of solid-state phase transformations and its kinetics responsible for micro-/nano-structure development in alloys and corresponding physical and mechanical properties. Transformation kinetics can be analyzed by various experimental techniques such as thermal analysis, laborious electron microscopy combined with extensive image analysis or by measuring changes in electrical resisti...
Alpha - beta transition in quartz
Lider, Mustafa Cem; Yurtseven, Hasan Hamit; Department of Physics (2011)
Alpha-Beta transition in quartz is studied using the Raman scattering. The Raman frequencies of some lattice modes are analyzed at various temperatures close to the alpha beta transition in quartz. For this analysis, the experimental data from the literature is used and the soft mode behavior of those Raman phonons is investigated . On the basis of the predictions of some models, the temperature dependencies for the Raman frequencies of the lattice modes which move towards zero (soft mode) and their bandwid...
Optoelectronic properties of Tl3InSe4 single crystals
QASRAWI, ATEF FAYEZ HASAN; Hasanlı, Nızamı (Informa UK Limited, 2010-01-01)
The crystal structure, temperature-dependent electrical conductivity, Hall coefficient, current-voltage characteristics, absorption spectra and temperature- and illumination-dependent photoconductivity of Tl3InSe4 single crystals were investigated. Tl3InSe4 crystallises in a body-centred lattice with tetragonal symmetry and belongs to the space group [image omitted]. The crystals are extrinsic p-type semiconductors and exhibit a conductivity conversion from p- to n-type at a critical temperature, Tc, of 283...
Citation Formats
M. C. Lider, “First order and second order phase transitions in quartz and related materials,” Ph.D. - Doctoral Program, Middle East Technical University, 2017.