EAGER: Magnonic logic devices with perpendicular magnetic anisotropy

Georgia State University Research Foundation, Inc., Atlanta GA

Investigators

Abstract

Current development of novel computing devices based on magnetic materials is aimed at improving efficiency and adding new functionalities to existing semiconductor based logic devices. One of the promising candidates, magnonic logic device, utilizes waves of magnetization in nano-structured magnetic materials to transfer and process information, and perform logic operations. Interaction between two or more waves in junctions of wave carrying magnetic wires is used to perform logic operations. Building such device requires the ability to guide waves in magnetic wires of various shapes as well as forming magnetic wire junctions. Any deviation of a magnetic wire shape from a straight wire results in unwanted wave reflection and scattering that significantly limits capabilities of magnonic logic devices. The proposed project will perform a feasibility study of using novel magnetic materials that have potential to overcome such limitations. It is proposed to evaluate feasibility of using ultra-thin magnetic films with preferred out-of-plane magnetization. These materials should allow for building magnonic logic devices with unrestricted geometries of magnetic information-carrying busses and logic junctions. The proposed research will have a broader impact in the field of microwave electronics and magnetic memory technology. In addition, the proposed research will be a unique training ground for future physicists and engineers. Georgia State University is the minority serving institution which graduates the largest number of minority students (primarily African-American) than any other public or private school in the country. This program will facilitate graduate and undergraduate student education in the areas of magnetism, optics and nanotechnology and provide a wide variety experimental skills among which nanofabrication will have most broad applications spectrum. The proposed research focuses on the feasibility study of the magnonic systems based on ferromagnetic materials with perpendicular magnetic anisotropy. Perpendicular magnetic anisotropy will ensure the out-of-plane magnetization of structures resulting in support of isotropic forward volume magnetostatic spin wave modes. The project aims at investigating forward volume magnetostatic spin wave propagation in structured ferromagnetic films with perpendicular magnetic anisotropy and evaluating feasibility of using these structures for magnonic logic devices. Multi-layered magnetic materials exhibiting perpendicular magnetic anisotropy will be used. Spin wave dispersion in these material systems is not significantly affected by spin waveguide shape variation. Therefore, propagation of spin waves will not be altered by the mode-mismatching induced by spin waveguide shape variation. Magnonic logic devices based on the proposed structures will demonstrate stable operation in absence of biasing magnetic fields while uniform external magnetic fields can be used to reconfigure their operation. The proposed project will result in fabrication and characterization of structured multilayered films with perpendicular magnetic anisotropy leading to the fundamental understanding of magnetization dynamics in these systems. That includes assessing losses via ferromagnetic resonance measurements, and measuring spin wave propagation in variable shape spin waveguides and spin waveguide junctions. Microwave vector spectroscopy combined with magneto-optical Kerr microscopy experimental techniques will be used. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.