Magnonic computing and signal processing
Spin waves (or quantized: magnons) are propagating collective excitations of magnetic spins. They provide an interesting and promising alternative for on-chip signal processing and computing. Fundamental circuit elements (magnonic transistor, logic gate, spin-wave bus) as well as more exotic devices (magnonic crystal, neuromorphic computing device, on-chip spectrum analyzer) were proposed, and in some cases, experimentally demonstrated. Although the numbers look promising in some figures of merit, with the currently available technology it is very difficult to challenge CMOS at its own game i.e. Boolean logic. However, spin-waves could excel in alternative computing architectures, where digital implementations are costly, e.g. in wave-based computing approaches and in RF analog signal processing.
Optically inspired computing devices based on spin waves
As the simple scaling of digital devices comes to physical limits, computing alternatives are heavily researched. One example are computing elements, where properties of matter are directly exploited in order to solve physical equations, perform pattern matching, conduct signal processing or pre-evaluate sensor data. One potential platform to efficiently perform complex computational operations by specialized hardware are so-called spin-waves. Spin-waves in ferro- and ferrimagnetic materials are propagating phase-coherent collective excitations of magnetic spins in form of precessional motion. However, spin-waves do not only propagate with very low losses: They interfere, they add-up, show non-linear behavior and potentially show even power gain and such they can be used as stand-alone computing elements. We try to exploit their properties and purposely manipulate them in order to build devices by adapting optical computing concepts, since spin waves have similar propagation characteristics than optical (electro-magnetic) waves. Our work focuses on Forward Volume Magnetostatic Spin Waves (FVMSW), i.e. the magnetic bias field is normal to the film plane, because isotropic propagation is desirable in spin wave devices.