Magnetic computing · Explore the mechanism
A spin-wave junction remembers
which way to send a signal.
Set the magnetic state, remove the external field, then send a wave. The crossing keeps its routing choice even when the source is paused.
01 / Set the memory
One crossing.
Two stored routes.
A brief external field sets the magnetization. Choose a state to begin.
Illustrative programming step: 100 mT applied briefly, then removed. A/B are teaching labels.
First, initialize A or B.
Stored magnetization shapes the turn. Arrows show the retained magnetic directions. Their rotation at the crossing creates a diagonal internal field ridge that redirects the wave.
Write the routeChoose A. Watch the initializing field disappear.
Send the signalRun, pause, then resume. The stored state stays.
Change the memoryChoose B. Compare the route and reveal the mechanism.
Slowed conceptual illustration, not a predictive physics solver. Experiment: continuous waves at 1.4 GHz in a 700 nm wide, 120 nm thick yttrium iron garnet (YIG) cross. The internal-field mechanism is calculated. Zero external bias does not mean zero internal field or energy use. Programming controls are illustrative; miniaturized networks, selective switching and pulsed routing were simulated. Nikolaev et al., Nature Materials (2026), doi:10.1038/s41563-026-02778-1.
Why does it turn, and what does “zero field” mean?
The memory is magnetic order
Magnetization remains aligned along the guides after the initializing field is removed. At the crossing, its direction rotates between the two guide axes. The associated internal field forms a diagonal ridge, steering the preferred signal route. +45° initialization favors the lower arm; −45° favors the upper arm, as in Fig. 2.
A wave, rather than material flow
The luminous pattern represents coordinated magnetic oscillations carrying a signal. No electrons or pieces of the material travel down these arms. Colors, wavelengths, timing and contrast here are schematic; weak transmission and reflections are omitted.
Zero external bias still leaves an internal field
“0 mT” describes the removed external bias field. The magnetic material still has an internal effective field. Writing, microwave excitation, detection and supporting electronics require energy; this is not a demonstration of zero energy use.
Experiment and proposed extensions
The measured crossing used a brief 100 mT initialization and continuous excitation at 1.4 GHz (Figs. 1–2). Smaller guides, networks, selective rewriting with combined fields, and short pulses were studied by micromagnetic simulation (Figs. 3–6). These buttons do not demonstrate experimental local switching without an applied field.