Abstract
This dissertation presents the study on novel magnetic nanoparticles (NPs) with unique structure-property relationship. Iron based magnetic NPs for this study have been synthesized using nanocluster deposition system by soft and energetic landing on the surface of silicon substrates, and studied with respect to their nanostructures, morphologies, sizes, shapes and magnetic and electric properties for two different projects: (i) advanced nano-sensor and monitoring of radiation detection for nuclear energy applications at high temperature, and (ii) advanced magnetic nanomaterials for ultrahigh frequency electronics.
In order to test the NPs compatibility for nuclear radiation detection and monitoring at high temperature, the iron-based NPs prepared using nanocluster deposition techniques by soft landing on silicon substrates were heat treated in argon, oxygen and vacuum environment up to 800 0C. The structure-property relationship pre- and post- heat treatment of the NPs have been studied. The NPs have shown stable morphology, shapes, phase and structure even up to 800 0C in vacuum environment. The results from the high temperature test and previous in-situ radiation tests are very promising for the application of the NPs as a radiation sensing material for monitoring radiation fluxes in the high temperature core of the nuclear reactors
A new CMOS-integration compatible soft magnet is developed by applying energetic impact of Fe/Fe3O4 core-shell nanoparticles onto tilted Si substrates for ultrahigh frequency applications. At room temperature, the in-plane uniaxial anisotropy is induced and tuned, which is interpreted by the uniaxial shape anisotropy of the ellipsoidal nanoparticles and the nanoparticle assembly alignment. Meanwhile, excellent magnetic softness and large resistivity are obtained in the nanocomposites at 5 kV. The good and adjustable uniaxial anisotropy and magnetic softness have been obtained with the large resistivities demonstrating excellent potential for high-frequency performance in miniaturized electronic devices for next generation (5G and 6G) wireless network.