Ultra-low energy threshold engineering for all-optical switching of magnetization in dielectric-coated Co/Gd based synthetic-ferrimagnet

Abstract

A femtosecond laser pulse is able to switch the magnetic state of a 3d-4f ferrimagnetic material on a pico-second time scale. Devices based on this all-optical switching (AOS) mechanism are competitive candidates for ultrafast memory applications. However, a large portion of the light energy is lost by reflection from the metal thin film as well as transmission to the substrate. In this paper, we explore the use of dielectric coatings to increase the light absorption by the magnetic metal layer based on the principle of constructive interference. We experimentally show that the switching energy oscillates with the dielectric layer thickness following the light interference profile as obtained from theoretical calculations. Furthermore, the switching threshold fluence can be reduced by at least $80\%$ to 0.6 mJ/cm${}^2$ using two dielectric SiO${}_2$ layers sandwiching the metal stack, which scales to 15 fJ of incident energy for a cell size of $50^2$ nm${}^2$.

References in corpus (2)

• Roadmap of spin-orbit torques
• Picosecond all-optical switching of magnetic tunnel junctions

Cited by in corpus (5)

• Design of an integrated hybrid plasmonic-photonic device for all-optical switching and reading of spintronic memory
• Energy-efficient picosecond spin-orbit torque magnetization switching in ferro- and ferrimagnetic films
• Enhancing All-Optical Switching of Magnetization by He Ion Irradiation
• Magnetostatics of Room Temperature Compensated Co/Gd/Co/Gd-based Synthetic Ferrimagnets
• Integrated magneto-photonic non-volatile multi-bit memory