“Magnonic nanoantennas” demonstrated: Optically-inspired computing with spin waves one step closer

Spin waves propagating in a magnetic material

Spin waves propagating in a magnetic material

BROOKLYN, New York, and MILAN, Italy, Thursday, May 5, 2020 – A cover article in the journal Advanced Materials demonstrates a new methodology for generating and manipulating spin waves in nanostructured magnetic materials. This work opens the way to developing nano-processors for extraordinarily quick and energy efficient analog processing of information.

The discovery was the result of a collaboration among a research group headed by NYU Tandon School of Engineering Professor of Chemical and Biomolecular Engineering Elisa Riedo; the magnetism group in the Physics Department at Politecnico di Milano, comprising Edoardo Albisetti, Daniela Petti and Riccardo Bertacco; Silvia Tacchi of the Istituto Officina dei Materiali of the Italian National Research Council (CNR-IOM) in Perugia; the Physics and Geology Department at University of Perugia; and the PolLux Beamline at PSI, in Villigen, Switzerland.

Spin waves, also known as “magnons”, are analogous to electromagnetic waves for magnetism, and propagate in materials such as iron in a way that is similar to that of waves in the ocean. Compared to electromagnetic waves, magnons are characterized by unique properties that make them ideal for developing miniaturized “analog” computing systems that will be much more efficient than the digital systems currently available.

Until now, modulating spin waves at will was extremely complex. The article published in Advanced Materialson March 5, 2020 presents a new type of emitters, called “magnonic nanoantennas,” which allow for the generation of spin waves with controlled shape and propagation. For example, it is possible to obtain radial wavefronts (such as those generated by throwing a stone into a pool of water), or planar wavefronts (as ocean waves on the beach), as well as creating focused directional beams. The article also demonstrates that, by using multiple nanoantennas simultaneously, interference figures can be generated “on command,” which is a necessary condition for developing analog computing systems.

The nanoantennas were realized by employing the TAM-SPL technique (developed at Politecnico di Milano in collaboration with Riedo’s group), which allows for the manipulation of the magnetic properties of the materials at the nanoscale. Specifically, the nanoantennas consist of minuscule “ripples” in the magnetisation of the material (called “domain walls” and “vortices”) that, when set in motion by an oscillating magnetic field, emit spin waves. Given that the spin waves’ properties are linked to the type and peculiar characteristics of these ripples, controlling them very accurately allowed to modulate the emitted waves as never before.

This work was funded by the European Union’s Horizon 2020 Research and Innovation Programme, under the Marie Skłodowska-Curie grant No 705326, SWING Project (Patterning Spin-Wave reconfIgurable Nanodevices for loGics and computing).

The article, entitled “Optically-inspired nanomagnonics with nonreciprocal spin waves in synthetic antiferromagnets” is available on the website of Advanced Materialshttps://onlinelibrary.wiley.com/doi/10.1002/adma.201906439

About the New York University Tandon School of Engineering

The NYU Tandon School of Engineering dates to 1854, the founding date for both the New York University School of Civil Engineering and Architecture and the Brooklyn Collegiate and Polytechnic Institute (widely known as Brooklyn Poly). A January 2014 merger created a comprehensive school of education and research in engineering and applied sciences, rooted in a tradition of invention and entrepreneurship and dedicated to furthering technology in service to society. In addition to its main location in Brooklyn, NYU Tandon collaborates with other schools within NYU, one of the country’s foremost private research universities, and is closely connected to engineering programs at NYU Abu Dhabi and NYU Shanghai. It operates Future Labs focused on start-up businesses in Brooklyn and an award-winning online graduate program. For more information, visit engineering.nyu.edu.