Date of Award

5-2018

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

Committee Chair

Corey Thompson

Committee Member 1

Christina Li

Committee Member 2

Jianguo Mei

Abstract

Double perovskite oxides make up an extremely large and diverse set of compounds in the realm of solid state chemistry. Capable of incorporating nearly every element of the periodic table, these perovskites possess tunable and mixed physical properties. As such, the substitutions of many elements into the various crystal structures of double perovskites have not been well explored. One such of these elements is Os, which displays a large range of possible oxidation states and the capability to create complex magnetic systems when paired with other magnetic cations in the B-site sublattice of double perovskites. I have undertaken several projects to synthesize and characterize new osmium containing double perovskite systems (AA’BB’O6). Through these studies I have gained insight into the magnetism of the SrLaMOsO6 (M= Mg, Zn, Mn) set of compounds of which Mg and Zn substitutions result in antiferromagnetic behavior, while the Mn compound appears to be ferrimagnetic. I have also studied the Ba2MOsO6, and BaLaMOsO6 (M= Mn, Fe, Co, Ni) systems which display a diverse set of properties. Ba2FeOsO6 is an example of a ferromagnet with high temperature transitions, while Ba2CoOsO6 shows two distinct structural polymorphs and a potentially independently ordering magnetic sublattice. The other compounds were shown to primarily be largely anisotropic with a range of behavior from ferrimagnetism to antiferromagnetism.

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