Researchers find way to control spin waves using light in an insulating material formed by magnetic layers

An international research team, including scientists from the Institute of Molecular Science of the University of Valencia (ICMol), has discovered how to control spin waves using light in an insulating material formed by magnetic layers. This could be a step towards a new generation of devices that store and transport information in a highly efficient way and with very low consumption.

If throwing a stone into a pond generates a wave that propagates over the surface of the water, something similar happens when the action of a magnet or a pulse of light, for example, propagates over a magnetic material – made up of small magnets (spines) connected to each other – and produces what is known as a ‘spin wave’.

This process allows information to be transmitted without the need to carry electrical charges, thus minimizing the energy losses that, in the form of heat, inevitably occur in conventional electronic devices. Therefore, using an insulating magnetic medium instead of an electrically conductive medium can open up the possibility of manufacturing very low energy consuming devices that do not require electric currents or electrodes to store and transport information.

The international research team of scientists from the Netherlands, Spain and Ukraine has managed to modulate the spin waves with ultra-short pulses of light – a trillion times less than a second – in a magnetic material consisting of layers of nickel, phosphorus and sulphur (NiPS₃).

“By selecting the appropriate wavelength at will, it is possible to activate and deactivate the propagation of these two-dimensional spin waves”, says Eugenio Coronado, a member of the Spanish team with Samuel Mañas, both researchers at the ICMol of the University of Valencia. “Since this propagation occurs on the surface of the material, the choice of a laminar material offers a very promising route for transmitting information in ultra-thin devices, as its thickness can be reduced to that of a monolayer of thickness atomic in the same way as in graphene”, he adds.

The results of this work constitute the first step towards manufacturing hybrid devices formed by photoactive molecules anchored on magnetic materials, in which the optical stimulation of the molecule with visible light can be transformed into a magnetic signal that propagates across distances of hundreds of nanometers.

This new technology is the basis of the European project SINFONIA (Selectively activated information technology by hybrid organic Interfaces) that the group of Valencia, led by Coronado, has just started in the framework of the FET-OPEN call of the H2020 program. Raised in the field of ICT, SINFONIA proposes the storage and transportation of information in hybrid interfaces formed by photoactive molecules and antiferromagnetic materials.