‘To boldly go where no man has gone befor’ is the famous mission of the starship Enterprise in the 1960s television series Star Trek. However, in reality, our ambition to explore uncharted regions in space is hampered by many obstacles, such as our communication capabilities, which still suffer from delays when transmitting and receiving information over great distances. For example, a message sent from Mars would take about 13 minutes to reach Earth, hardly an ideal situation in emergencies.
In the quest to improve ultrafast communications, researchers at A*STAR’s Institute of Materials Research and Engineering (IMRE), who were previously working at A*STAR's Data Storage Institute (DSI), are tapping on spin-wave-mediated communication based on ultrathin magnets.
Using sophisticated lithography processes, the researchers previously created a specific class of metamaterials called magnonic crystals. In the present study, the researchers used a unique type of magnonic crystal that possesses magnetic monopole-like behavior, a property that does not exist in nature. The resulting structures are known as artificial spin ice (ASI) systems, named after the distinctive arrangement of water molecules in ice, where each oxygen atom is surrounded by four neighboring hydrogen atoms in space.
“ASI systems are attractive due to their unique static and dynamic features. For application purposes, control and tuning their characteristics will be essential,” said Abhijit Ghosh, a Scientist at IMRE. “Our study of the high-frequency dynamics study in ASI systems and other types of magnonic crystals are aimed at unveiling the prospects of such structures for ultrafast futuristic communications.”
Using experimental techniques such as high-frequency ferromagnetic resonance spectroscopy in combination with micromagnetic simulations and semi-analytical techniques, Ghosh and his team found that the geometrical parameters of the nanostructured magnets strongly influence their high-frequency (microwave) characteristics.
The team then explored how introducing different geometrical parameters—generated through nanofabrication—influenced the magnetic properties of their ASI system. They showed that manipulating the dimensions of the magnonic crystals and the thickness of the magnetic layers could enable scientists to design ASI systems for specific functions.
In the future, ASI systems could be useful in diverse and intriguing applications beyond communications, such as neuromorphic computing for developing artificial intelligence and enhancing our data storage capabilities, added Ghosh.
