Nanoscale engineering of barium titanate using copper (II) - tungsten (VI) dipole pairs
Date
2019-05
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Abstract
BaTiO3 is a perovskite in which structural phase transitions are induced through polarization, and currently is one of the most widely used materials for ceramic capacitor technology. Above the TC1 (Curie temperature one), BaTiO3 exists as a single perovskite cubic structure. Based on theory stemming from the Clausius-Mossotti relation, polarization-induced structural phase transitions can be engineered by increasing net energy conditions in the lattice. Past research indicates that the addition of discrete and localized electric fields induce such phase transitions. Furthermore, the substitution of permanent dipoles into BaTiO3 have been shown to result in localized electric fields that are controllable and lend to enhanced electrical properties of materials possessing such compositions. To further investigate improvements in electrical properties by dipole substitution, compositions of Ba(Cu2+, W6+)xTi1-2xO3, with x equal to 0, 0.00125, 0.0025, 0.005, 0.01, 0.025, 0.05, and 0.1 were prepared from solid oxide starting materials using solid-state synthesis reaction methodology. Room temperature X-ray Powder Diffraction and temperature-dependent resistivity measurements have been conducted to characterize the synthesized materials. Experimental results demonstrate significantly greater electrical resistivity values when compared to undoped BaTiO3 as well as Ba(B12+, B5+)Ti1-2xO3 analog materials. As dipole substitution is increased, electrical resistivity systematically increases.
Description
Thesis completed in partial fulfillment of the requirements for the Alfred University Honors Program.
Type
Thesis
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Keywords
Honors thesis, Nanoscale engineering, Materials science, Barium titanate