Nano Letters cover spot for article on Ultrafast Demagnetization Control
In collaboration with their colleagues from Sweden, researchers from HFML-FELIX Laboratory and Radboud University demonstrated how magnetic memory combining plasmonics and magnetism is poised to dramatically increase the bit density and energy efficiency of light-assisted ultrafast magnetic storage. This landed them the cover spot on the December edition of Nano Letters Journal.
The study explored the possibility to concentrate the light using plasmonic nanostructures, and as such, increasing the efficiency of light-induced effects on magnetization. This in addition to being able to focus light way below the diffraction-limited spot size. To do this, they used nanometer-sized dots made of magnetic alloy TbCo on top of gold nanocones (which was a challenging task on a manufactural level), and sensitive magneto-optical detection to avoid laser-induced damage.
From this experiment, they discovered that, indeed, it was possible to concentrate the light energy with the help of nanostructures. The increased demagnetization of the magnetic TbCo tips functions as proof to support their theory, with the assumption that light is focused into the magnetic tips. Moreover, the effects of various plasmon resonances could be distinguished, revealing a platform where ultrafast demagnetization is localized at the nanoscale and its extent can be controlled at will, rendering it multi-state, and potentially opening up so-far-unforeseen nanomagnetic neuromorphic-like systems operating at femtosecond timescales controlled by light.
To build upon their findings, the researchers are currently looking into the possibility of making magnetic tips from a ferrimagnetic alloy that could be switched with the help of single laser pulses, and thus demonstrate the enhanced efficiency of switching.
Ultrafast Demagnetization Control in Magnetophotonic Surface Crystals
Kshiti Mishra, Richard M. Rowan-Robinson, Agne Ciuciulkaite, Carl S. Davies, Alexandre Dmitriev, Vassilios Kapaklis, Alexey V. Kimel, and Andrei Kirilyuk
Nano Letters 2022, 22, 23, 9773–9780