Our modern society is driven by data which provides a continuous demand for innovative and sustainable data processing devices. The fiber-optic networks have enabled nearly lossless Tb/s transfer of data, encoded in the amplitude and phase of a optical wave. At the same time data processing at Tb/s rates, in step with the data flow remains a great challenge. Even if we manage to process a bit of information in a single ps (corresponding to Tb/s), repeating this event at Tb/s rates will result in an explosive, unaffordable energy costs! Therefore, there is a need to develop new ways and technologies for faster and more energy-efficient data processing and storage.
Magnonics, is widely seen as one of the most appealing solutions to this problem. Instead of light waves, magnonics exploits spin waves– the collective propagating precession of spins in magnetic materials. They are characterized by very high Thz frequencies, enabling Tb/s data processing rates, low dissipation, and at the same time can be scaled down to 1 nm. Although several methods to generate and detect various spin waves excitations are known, we still are unable to make the waves to interact. This turns out to be a great issue as the computation is a strongly nonlinear process in which multiple signals must interact. Nonlinearity is what hampering Thz spins waves from practical applications. How can magnonics be pushed into the THz domain and enter the nonlinear regime? And how large are the THz nonlinearities? In the ASTRAL project the research team will tackle these fundamental key mechanisms.
Ultrashort large amplitude spin-wave pulses
The research team aims to enter the nonlinear regime of THz magnonics by generating ultrashort large amplitude spin-waves pulses. Such pulses being very short in time would have all their energy very much condensed, such that truly large-amplitude spin-wave excitation is realised. These pulses, similarly, to femtosecond pulses of light, can be generated out of broadband spin-wave packets in which individual spin-wave components interfere constructively such that a solitary spin-wave pulse is achieved, with the amplitude limited only by the bandwidth of the packet – opening up a way towards nonlinear interaction and controlling magnetic bits. “We will focus on antiferromagnets, where SW frequencies can easily reach the THz landmark and follow a linear, so-called relativistic, dispersion relation”, Dmytro Afanasiev explains. He also says: “if realised such pulses can zip undisturbed over long distances unlocking the nonlinear regime of interaction between the pulses, other spin-waves and even macroscopic spin textures.
ASTRAL will exploit the exclusive ability of light to initiate ultrafast spin dynamics and will attempt to interconvert femtosecond laser pulses into large-amplitude ultrashort SW pulses. Although the idea is fundamental in nature, it will create new paths to ground-breaking new computing technologies.