Theses and Dissertations at Montana State University (MSU)
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Item An electron paramagnetic resonance study of the ethylammonium-, methylammonium-, and acetamidinium-tetrachlorocuprates(Montana State University - Bozeman, College of Letters & Science, 1968) Amundson, Paul HenryItem Electron paramagnetic resonance of anilinium tetrachlorocuprate and ethylenediammonium tetrachlorocuprate(Montana State University - Bozeman, College of Letters & Science, 1976) Bergstrom, Richard AllenItem The forbidden hyperfine paramagnetic resonance spectrum of vanadium in magnesium oxide(Montana State University - Bozeman, College of Letters & Science, 1966) Dickey, David HughItem The temperature dependence of the forbidden-hyperfine spectrum of rare earth S-state ions in cubic crystals(Montana State University - Bozeman, College of Letters & Science, 1970) Worsencroft, Don KayItem Electron paramagnetic resonance spectra of trivalent chromium in MgO(Montana State University - Bozeman, College of Letters & Science, 1969) Dickey, David HughItem An EPR study of the two-dimensional magnetic solitons(Montana State University - Bozeman, College of Letters & Science, 1996) Subbaraman, KalaItem Electron paramagnetic resonance of lithium niobate heavily doped with chromium and lithium niobate codoped with magnesium and iron(Montana State University - Bozeman, College of Letters & Science, 2010) Jorgensen, Jonathan David; Chairperson, Graduate Committee: Galina I. MalovichkoIn this thesis, electron paramagnetic resonance (EPR) was utilized in measuring and characterizing the dopant ions in three samples of lithium niobate (LiNbO 3). The first sample was LiNbO 3 of congruent composition doped with 0.25% mol chromium (LiNbO 3:Cr). This sample was studied in detail using two microwave frequencies, 9.4 GHz and 34.4 GHz. It was also studied both at room temperature and at 10 K. Several centers including complexes of Cr-Cr pairs were observed in addition to the most prevalent axial Cr ³+ center. The other two samples were LiNbO 3:Mg:Fe, one of congruent composition and the other of stoichiometric composition. The congruent composition contained 6% mol Mg and 0.02% mol Fe, while the stoichiometric sample contained 0.45% mol Mg and 0.01% mol Fe. The stoichiometric composition contains all the same centers observed in the congruent material, plus two additional centers. Since the stoichiometric material provides EPR spectra of much higher resolution, those centers existing in both compositions were characterized more accurately from the stoichiometric material. A discussion of models for dopant center symmetries, dopant positions in the LiNbO 3 lattice, and the charge compensators required by each center is provided. It is shown that charge compensators play an important role in explaining the existence of the additional centers observed in the stoichiometric material.