Characterisation of powders using\ud microwave cavity perturbation
Cuenca, Jerome A.
The contribution in this thesis is a novel application of microwave cavity perturbation in\ud the characterisation of the fundamental properties of powders.\ud This thesis shows that microwave cavity perturbation is very good at characterising the\ud magnetite to maghemite phase change through dielectric and magnetic measurements.\ud This is very important in material science since conventional techniques, though powerful\ud and are able to verify the change, use complex methods. Quantifying di�erent forms of\ud magnetite and maghemite is important for magnetic drug delivery and EMI absorbers.\ud This thesis shows that microwave cavity perturbation can be used to measure the impurities\ud of nanodiamonds through simple dielectric measurements. This is important because\ud other methods again may involve complex systems, while microwave cavity perturbation\ud can provide a fast, sensitive �gure of merit. Nanodiamonds are used in drug delivery and\ud bio-labelling which requires accurate surface characterisation.\ud This thesis shows that microwave cavity perturbation can measure in-situ temperature dependent\ud and photocatalytic responses in materials such as titania using a novel correction\ud procedure. Microwave cavity perturbation has not been used with this correction procedure\ud before which simpli�es the system when monitoring systematic errors. This work is\ud important as it shows how simple microwave cavity perturbation systems can provide insight\ud to thermally activated processes and veri�cation of some photocatalytic mechanisms\ud in powders for use in pigmentation and light induced drug delivery.