CAREER: Spin Plasmonics for Ultrafast All-Optical Manipulation of Magnetization in Hybrid Metal-Ferromagnet Structures

Northeastern University, Boston MA

Investigators

Abstract

Nontechnical Description: Efficient computation, information processing and digital communications rely on technologies utilizing magnetic materials. Recent work has shown that optical laser pulses can be used to manipulate magnetic material properties, promising access to stored data at breakthrough speeds, significantly faster than in current computing devices. However, the fundamental mechanism of this process, as well as the limit to size of the individual memory units are not yet fully understood. This project aims to realize optical control over magnetic memory at unprecedented speed and density, using hybrid materials comprising metallic and magnetic nanostructures. The intertwined optical, thermal and magnetic effects in these materials are examined through a set of experimental and computational studies. The proposed work stands to impact society in multiple ways. Ultrafast, nanoscale optical control of magnetic materials enables data storage, memory and computational devices for applications such as web search engines and online commerce. The integrated education plan incorporates significant outreach, involving students beginning from grades 7-12 to the graduate level. Participating students are exposed to several rapidly growing fields including materials science, optics, and nanotechnology, while additionally interacting with industrial collaborators. Technical Description: All-optical switching of magnetization has emerged as an exciting topic in modern magnetism. In addition to the requirement of fully understanding its rich physics, all-optical switching must compete with the areal densities attainable in current storage devices for it to be technologically compelling. The goal of this project is to utilize a new class of hybrid materials consisting of noble metals and ferromagnets, where the exceptional field confinement and strong optical spin of surface plasmons are leveraged to realize nanoscale ultrafast all-optical switching of magnetization. The synergistic research and education activities include: (1) achieving manipulation of out-of-plane and in-plane magnetization using optical spins of surface plasmons; (2) investigating the dynamics of different carriers and their interactions in hybrid metal-ferromagnet structures; (3) gaining new insights into the mechanism of nanoscale, ultrafast magnetization reversal; and (4) engaging students, especially those from underrepresented groups, and educating them with solid fundamentals and knowledge of cutting-edge applications. Outcomes of this project potentially enable new material systems for data storage and information processing technologies, with the advantages of high speed, high capacity, and low power consumption.