From Nanoscale Design to Functional Integration of Magnetic Nanoparticle Assemblies: A Gas-Phase Strategy

The self-assembly of magnetic nanoparticles under external magnetic fields holds great potential for the facile fabrication of functional magnetic components with a wide range of applications. This work employs a technique based on electrically charged gas-phase magnetic nanoparticles, demonstrating an additional level of control when forming one-dimensional assemblies, so-called nanochains, as an electric field can be used in addition to the magnetic field during the deposition process. This dissertation covers the entire process, from generating charged gas-phase magnetic nanoparticles with different compositions and tuning their assembly process through electric fields to their direct integration onto desired substrates, developing practical applications, and conducting detailed experimental and computational magnetic characterizations and analysis. This work shows that the interplay of the electric and magnetic fields during the deposition process enables the tuning of the spatial distribution of structures on the surface. Furthermore, it demonstrates that this approach facilitates control over the composition of nanoparticles and supports the sequential deposition of different material systems onto each other. Utilizing the direct integration capability of this method, this thesis showcases the creation of magnetically responsive soft films and nanoscale magnetoresistive devices. Finally, the magnetic properties of the fabricated structures are characterized in detail. A combination of magnetometry protocols is used to characterize the structures from an ensemble-averaged perspective. In addition, X-ray microscopy, nanochain devices, and micromagnetic simulations are used to study the structures from a single nanochain point of view.