PhD Thesis Defense: Nanomagnetic Logic by Photothermal Excitation of Magnetic Nanostructure Networks

Artificial spin ices (ASIs) are systems made up of single-domain nanomagnets which are used to study geometrically frustrated systems and have been proposed for use in novel computation applications. Depending on the arrangement of the nanomagnets in an ASI the system can have degenerate ground states due to the system not being able to minimize all the magnetostatic interactions at the same time. Storing information with the direction of magnetization while being able to compute the information via the magnetostatic interactions within the ASI would crack the von Neumann bottleneck allowing for faster and more efficient computing. The duality of the problem however is that the nanomagnets within the ASI have to be stable enough to store information (not fluctuate between 1 and 0) while at the same time having interactions that are strong enough to compute the information (change the state of a bit). One solution is to selectively lower the energy barrier that stabilizes the magnetization direction in the desired nanomagnets when computing. The selective heating, as shown in this project, can be achieved in ASI with thermoplasmonics by carefully designing the optical properties of the nanostructures. In this presentation we will learn the design process of a reconfigurable nanomagnetic logic gate, with its various design parameters and complications, before showing EXPERIMENTALLY the result of a Boolean logic operation.