Date of Award

2011

Document Type

Campus Access Dissertation

First Advisor

Hans-Conrad zur Loye

Abstract

The discovery of new materials with potentially interesting properties is significant in order to allow for the study of structure-property relationships. We aim to discover new materials via the growth of single crystals. Flux crystal growth has several advantages over other methods, including low reaction temperatures and easy reaction setup. Novel Fe, Co, Rh, Hf and Ln containing oxides have been synthesized from molten hydroxide fluxes. Their crystal structures were solved by single crystal X-ray diffraction, and their magnetic and electrical properties have been studied. Unconventional magnetism was found in the new compound Ba4KFe3O9. A group of one-dimensional oxides belonging to the 2H-perovskite related family were synthesized. Sr5Co4O12, one member of the 2H-perovskite related family, exhibits a complicated interplay among valences, crystal structure, and magnetism. Several high oxidation state oxides, including Sr2-xLnxFeO4 (Ln = Nd, Sm, Eu), SrTbO3, and BaTbO3, have been successfully crystallized from molten hydroxides, thanks to the highly oxidizing nature of molten hydroxides. Additionally, two potassium hafnates were crystallized in open and sealed reaction vessels, respectively, under otherwise identical reaction conditions, indicating the important role of water content in molten hydroxide synthesis.

Rights

© 2011, Qingbiao Zhao

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