SFB/TRR 173 SPIN+X

What is magnonics?

What is a spin wave?

 

Spins obey similar laws of physics as spinning tops: If a spinning top receives a shock perpendicular to its axis of rotation, it does not flip over, but its axis of rotation starts to rotate. We call this phenomenon precession.

Spins also begin to precess when they are deflected from their rest position. Unlike the gyroscope, however, this deflection is not achieved by a mechanical impact, but by the brief action of a magnetic field on the spin. In a magnet, where spins are arranged in a lattice-like structure, the precession of a spin is transmitted to its neighbors and propagates through the magnet. We speak of a spin wave.

What is a Magnon?

In modern physics. each wave can be associated with a particular particle. The best known is the light particle, the photon. The magnon is the particle assigned to spin waves.

What is magnonics?

Magnonics deals with spin waves and their propagation in magnetic solids. Similar to in spintronics spin waves as information carriers offer the advantage that electrons do not have to travel through the solid during data transmission, which only very small losses occur. Due to the low losses, only very little heat is which can be used to design components for computers, for example, which are smaller, more efficient and faster than the smaller, more efficient and faster than existing chips.

Spin waves offer an additional advantage: As with water waves, two spin waves overlap so that that wave crests and troughs can cancel or amplify each other. This phenomenon is called called interference (see left graph).

Whether cancellation or amplification occurs at a particular point depends on the phase of the waves i.e. their distance or delay from each other (see right graph).

In the spin-wave computer, information can be transmitted and processed in this phase of the waves. This offers a variety of new possibilities for the realization of components for circuits.

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