'Magnetic domain wall' circuit design could enable magnetic wave-based computing - little or no electricity required

Creating a practical magnetic-waves-based device requires efficient modulation of spin-wave propagation

Researchers at MIT claim to have created a novel circuit design that, they believe, could enable practical magnetic waves-based computing, requiring little to no electricity.

According to researchers, this circuit can modulate the magnitude and phase of a spin wave with the help of a nanometre-wide "magnetic domain wall."

For the past several years, researchers have been working on magnetic-based "spintronic" devices, which are said to require relatively little power to run. In addition, they generate nearly zero heat as a result of their operation.

Such "spintronic" devices work by leveraging the "spin waves" in magnetic materials with a lattice structure.

Spin waves are propagating disturbances in the ordering of magnetic materials. These collective excitations happen in magnetic lattices with continuous symmetry.

Creating a practical spintronic device requires efficient modulation of spin-wave propagation. This modulation results in a measurable output that can be used to carry out some sort of computation.

In the current study, the research team used a pattern of nickel/cobalt nanofilms and layered it with some specific magnetic properties to enable it to handle a large volume of spin waves.

The team then placed a customised "magnetic domain wall" in the middle of the magnetic material. The "wall" served as a nanometre-sized barrier between the two neighbouring magnetic structures. The entire system was then incorporated into a circuit.

In the next phase of their experiment, the researchers excited constant spin waves in the magnetic material on one side of the circuit, which caused the waves to pass through the "wall" and eventually spinning of its magnons (a collective excitation of the electrons' spin structure) in the opposite direction.

As a result of this spinning of magnons, a dramatic shift was observed in the wave's angle (phase) and a little drop in its magnitude (power).

The team was able to detect the output using an antenna on other side of the circuit.

The researchers believe such innovative circuit designs could allow creating practical spin wave-based computing devices for certain tasks, such as, signal-processing. The team is now planning to build a functional wave circuit that would be able to perform basic computations.

The detailed findings of the study are published in journal Science.

This is, however, not the first study attempting to exploit magnetic properties of materials to design low-power computing devices.

Last year, researchers at MIT and Brookhaven National Laboratory said that they had devised a new approach to control magnetism in thin-film materials, which could eventually enable CPUs with much lower power demands.

Earlier in 2016, Durham University landed a £7m grant to conduct research into 'nanosize magnetic whirlpools' or 'magnetic skyrmions', a branch of quantum mechanics that could drastically improve data storage capacities and processing speeds.