All-optical control of ferromagnetic thin films and nanostructures

TLDR

Light–magnetism interactions, exemplified by Faraday and Kerr effects, have long been used to probe magnetic materials, and recent studies show that polarized light can deterministically switch magnetization without external fields in certain ferrimagnets. The study aims to demonstrate optical control of ferromagnetic materials, from thin films to multilayers and granular films, for the first time. The authors achieve this by optically manipulating ferromagnetic thin films, multilayers, and granular films, targeting applications in ultra‑high‑density magnetic recording. The results reveal that optical control of ferromagnetic materials is a general phenomenon, challenging existing theory and promising major advances for data memory and storage technologies.

Abstract

The interplay of light and magnetism has been a topic of interest since the original observations of Faraday and Kerr where magnetic materials affect the light polarization. While these effects have historically been exploited to use light as a probe of magnetic materials there is increasing research on using polarized light to alter or manipulate magnetism. For instance deterministic magnetic switching without any applied magnetic fields using laser pulses of the circular polarized light has been observed for specific ferrimagnetic materials. Here we demonstrate, for the first time, optical control of ferromagnetic materials ranging from magnetic thin films to multilayers and even granular films being explored for ultra-high-density magnetic recording. Our finding shows that optical control of magnetic materials is a much more general phenomenon than previously assumed. These results challenge the current theoretical understanding and will have a major impact on data memory and storage industries via the integration of optical control of ferromagnetic bits.