Venugopal, Aneesh2022-01-042022-01-042021-09https://hdl.handle.net/11299/225870University of Minnesota Ph.D. dissertation. September 2021. Major: Electrical Engineering. Advisor: Randall Victora. 1 computer file (PDF); viii, 177 pages.Perturbations of the magnetic order, known as spin-waves or magnons, within a ferri- or ferromagnet can exhibit nonlinear properties. The nonlinearity of the magnons can be exploited for information processing applications and for understanding fundamental aspects of nonlinear processes. When using insulators such as Yittrium iron garnet (YIG), various functionalities such as signal processing can be realized in the absence of Ohmic losses. Moreover, the small wavelengths of spin waves can also help with the miniaturization of devices. Such advantages have made magnons attractive for a wide variety of applications ranging from communications to logic circuits. Although magnons have been studied in the past, precise understanding and the details of various nonlinear processes are still largely lacking. Device design is often based on trial-and-error approaches with regard to magnonic properties. Efficient and robust design, however, requires a deterministic understanding of material behavior. Moreover, given the long experimental cycles involved in device design, the ability to predict properties accurately is crucial. In this thesis, I will discuss the development of a high-speed CUDA-GPU (graphics processing unit)-based parallel platform to study magnons that are created by microwave excitation of magnetic materials. The goal is twofold: to enable a better understanding of nonlinear properties and to improve device design capabilities. Device characteristics of magnet-based frequency-selective limiters (FSLs) used for microwave signal processing are studied using simulations involving rigorous calculations of dipolar-, exchange-, and thermal-magnetic fields. These studies offer beneficial insights into the role of physical processes like higher-order scattering on the device behavior. A key requirement in many applications is the dynamic control of the threshold field -the minimum microwave field needed to turn on the nonlinear behavior in a magnetic sample. The ability to dynamically vary the threshold field using an additional microwave is explained analytically and demonstrated using simulations. The importance of magnon-phase in the nonlinear processes is also explicitly demonstrated. Despite the crucial role of magnon-phase in nonlinear physics, few studies focus on the impacts of magnonic phase-noise. I have developed an analytical theory to understand the impacts of magnon phase noise. The conclusions of the theory are verified using micromagnetic simulations.Magnetic recording comprises highly nonlinear processes that, unlike perturbative effects, involve the reversal of magnetization. Using micromagnetic simulations, I designed a high-density magnetic recording scheme employing state-of-the-art heat-assisted and bit-patterned techniques. Even after considering noise factors such as jitter and track misregistration, the design provides an extremely high density of 16 Terabits per square centimeters (Tbpsi).enmagneticsnonlinearityspin waveThesis or Dissertation