Collaborative Research: Ferrimagnetic Insulator Based Bilayers for Interface-Driven Topological Spin Textures

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NON-TECHNICAL DESCRIPTIONData is everywhere. It is generated at an accelerating pace by the devices we carry with us, embedded electronics in our homes and cars, and increasingly powerful computers and servers. This requires an enormous amount of energy for data creation, storage, and transmission. Innovations in data storage and processing are needed, and conventional electronics based on semiconductors are not equal to the task. Spintronics combines electronics with spin, an intrinsic property of elementary particles. The goal of this project is to develop a new material platform for spintronics, allowing new types of devices for energy-efficient memory and computing. Investigators will focus on heterostructures consisting of ultrathin magnetic films with an adjacent metallic layer. Investigators will grow high-quality bilayer films, characterize interactions at the atomically sharp interfaces, and optimize their properties for use in applications. This fundamental research could lead to portable, nonvolatile memory devices that are smaller in size, higher in density, and more energy efficient than those currently available. Undergraduate and graduate students will be trained to work in the critical science and technology fields to support an innovation-driven economy. The PIs will jointly teach a course on spintronics as well as expand a course on “Being Human in Physics” to both of their institutions.TECHNICAL DESCRIPTIONMagnetic skyrmions are a promising candidate for future ultrahigh-density, high energy efficiency magnetic memory devices. They exhibit robust topological stability, have nanoscale sizes, and a low electrical current is required to write, erase, and transport them. In order for skyrmion-based next-generation magnetic memory technology to become a reality, the fundamental interactions at the interfaces of magnetic bilayers need to be thoroughly understood, including exchange coupling, Dzyaloshinskii-Moriya interaction, and magnetic anisotropy. These interactions need to be judiciously tuned to host nanometer-sized skyrmions at room temperature. To achieve this goal, the PIs pursue a collaborative research project on ultrathin magnetic garnet-based bilayers as energy-efficient spintronic materials. The team integrates epitaxial film growth with advanced spectroscopy methods and aims to achieve the following goals: (i) establishing the structure-property correlation via a rapid feedback loop of growth and spectroscopy characterization; (ii) optimizing bilayers for skyrmions with desirable characteristics and chiral domain wall motions with record-breaking velocity; and (iii) exploring a new class of bilayers consisting of an epitaxial ferrimagnetic insulator film and a van der Waals overlayer.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.