FET: Small: Magnonic Active Ring Memory and Logic

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The size of modern data centers is growing exponentially due to the rapid development of Big Data techniques, Internet of Things (IoT), and Bioinformatics. Magnetic storage technology has been proven to be the core platform for cloud computing and Big Data storage. All magnetic storage devices can be classified as either sequential-access memory or random-access memory. For instance, in order to read out one bit in magnetic tape, the tape should be wound and the reading head placed in contact with the desired bit (sequential access). In contrast, any bit in magneto-resistive random-access memory (MRAM) can be accessed immediately at any given time. Regardless of the access process, the existing magnetic memory devices, including magnetic tape, hard-disk drives, and MRAM inherit one fundamental restriction: they are based on the magneto-resistance effect, which limits the number of bits which can be read out at a time. In turn, this imposes time constraints for a large magnetic database search. This problem has stimulated search for alternative methods for magnetic bit read-out (e.g., multi-head multi-track magnetic memory). Overall, there is a great need for a novel technology for parallel magnetic bit read-out and processing. The project will also enhance the educational experience of undergraduate, graduate and underrepresented students by via mechanisms for including them in the project, and thereby contributing to the much-needed technological-workforce development.In this project, a new type of magnetic memory using spin waves for information read-out and processing will be developed. Spin waves — or magnons, the quanta of spin waves — represent the excitations of the electron spin subsystem in magnetically ordered media and are observed in ferro- and ferri-magnets, as well as in anti-ferromagnets. The coherence length of spin waves in ferrite structures may be as large as one centimeter at room temperature, allowing one to exploit spin wave interference. The operation of spin-wave devices is similar to optical-holographic devices, which use coherent optical beams for information retrieval. The uniqueness of the spin-wave approach is the ability to combine holographic logic units with magnetic memory. This project aims to explore the feasibility of using spin waves for parallel magnetic bit read-out, to investigate device immunity to structure imperfections, and to study a combination of magnonic and electronic circuits. The result of this transformative research will add to the core knowledge in the area of material science, signal processing, and computer engineering.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.