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Spinoptical nanoantenna-assisted magnetic storage at few nanometers on femtosecond timescale

Periodic Reporting for period 2 - FEMTOTERABYTE (Spinoptical nanoantenna-assisted magnetic storage at few nanometers on femtosecond timescale)

Reporting period: 2019-03-01 to 2020-02-29

FEMTOTERABYTE develops the conceptually new paradigm for ultra-dense and ultrafast magnetic storage that is envisioned to bring the technological frontier in the storage density to tens of Terabytes per inch2, while taking the operation speed for read-write into the THz. We foresee to achieve this in an all-optical platform that allows deterministic, non-thermal, low-energy, ultrafast magnetization switching at few nanometers and potentially down to a molecular length-scale.

The main building block of this technology is the antenna for light, able to operate with the optical angular momenta at a nanoscale. The project is set to develop the fundamentals for such a memory unit, and to demonstrate it in practice and in operation, mapping its suitability for future upscaling towards industrial implementation in devices.

An innovative chemical/physical approach to the preparation of magnetic-plasmonic hybrids has been developed by assembling chemically prepared colloidal magnetic nanoparticles on physically fabricated plasmonic nanoantennas. The synergy between these two worlds allows for extreme versatility in the design and preparation of innovative optomagnetic architectures.
The project designed and nanofabricated various spinoptical nanoantennas that are able to concentrate light at several nanometers and that combine nanoplasmonic and nanomagnetic (including single-molecule magnets) elements. Through extensive modeling supported and guided by experimental feedback we have achieved an optimized design of the spin-optical nanoantenna to generate angular momentum hot spots in nanomagnets and magnetic films, as well as the optical excitation conditions to avoid relevant photoinduced heating. The fundamentals of the optical momentum transfer and its relevance to the all-optical magnetisation switching have been assessed. The ultrafast optical experiments on these systems revealed their potential suitability for building the nanoscale ultrafast memory units.
We aim at all-optical magnetisation switching at the scale of few nanometers with the help of spin optical plasmic nanoantennas. If this goal is reached, it will unveil by far the fastest and one of the smallest reliably operating memory units.A combined study of angular momentum amplification and localization together with nanoscale thermal effects and their control is beyond the state of the art and the results achieved establish our concept of spinoptical nanoantenna for contemporary all-optical-switching applications. The significant impact is expected in magnetic memory storage, but also in relevant magnonic and other lower frequency technologies for the information processing and in sensing applications.