Characterization of ricinoleic acid coated spinel nanoparticles and microfabrication of a four point device for nanowire electronic conductivity measurement
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Abstract
I. Characterization of Ricinoleic Acid Coated Spinel Nanoparticles
Magnetic nanoparticles are of great interest today due to their potential contributions to the development of new imaging technologies. Ferrites, in particular, stand out because of their significant magnetic susceptibilities and relative chemical stability as candidates for a number of applications in technological, biomedical and environmental research. In this chapter, the vibrating magnetic susceptibility studies of a series of ricinoleic acid coated non-magnetite spinels with the form MFe2O4 (M= Co, Ni, Mn, Zn) will be presented. Results indicate similarities between the magnetic saturation susceptibility (Ms) values obtained for Ni and Mn samples (55.9 emu/g and 48.8 emu/g, respectively), and published values for spinel nanoparticles coated with oleic acid and other surfactants (~50 emu/g and ~20-50 emu/g respectively). Co samples demonstrated a low Ms of 5.06 emu/g in comparison to published results (~6-90 emu/g). These results can be attributed to small core size and/or presence of other species during measurements such as cobalt oxide. Finally, the Zn sample demonstrated dispersion difficulties and low magnetic susceptibility and was subjected to a series of pH dependent studies resulting in a maximum Ms of 17.7 emu/g at pH 8. Maximum magnetic susceptibilities have been attained by optimization of facile air-stable hybrid co-precipitation hydrothermal syntheses demonstrating how magnetic susceptibilities can be affected by the reaction conditions, which affect the size of nanoparticles. [TRUNCATED]
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Thesis (M.S.)--Boston University