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http://hdl.handle.net/11375/18730
Title: | A Study of The a-β Phase Transformation in A1PO4:Fe^3+ and Quartz by Electron Paramagnetic Resonance |
Authors: | Lang, Robert |
Advisor: | Calvo, C. Datars, W. R. |
Department: | Physics |
Keywords: | phase transformation;electron;paramagnetic resonance;hydrothermal crystals |
Publication Date: | Oct-1971 |
Abstract: | <p> The a-β phase transformation was studied in hydrothermally grown crystals of A1PO4 by measuring the spin-Hamiltonian parameters of Fe^3+ as a function of temperature. </p> <p> The theory of the Blume-Orbach mechanism for the zero-field splitting of s-state ions was generalized and used to calculate the D-tensor of the spin-Hamiltonian. The experimentally observed temperature variation of the spin-Hamiltonian was interpreted in terms of a temperature-dependent point-multipole model of the charge distribution in the crystal lattice. </p> <p> A similar study of the a-S phase transformation in quartz was attempted but E.P.R. measurements could only be taken up to 450°C (123°C below the transformation temperature) because of the instability of the Fe^3+ center at higher temperatures. </p> |
URI: | http://hdl.handle.net/11375/18730 |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
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Lang_Robert_1971_Phd.pdf | 5.71 MB | Adobe PDF | View/Open |
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