As electronics get faster and smaller with more densely packed elements, Joule heating from electron motion and the resulting collisions becomes more prominent. Heat limits the performance of electrical devices and requires built-in cooling methods—from fans to heat sinks. A device that transports information without moving electrons would avoid such power dissipation, and so-called magnonic devices would do just that.
In magnonics, spin waves embody and transfer information through the collective precessions of electron spins that transport angular momentum while the electrons stay put. Although related, magnonics is distinct from spintronics, which uses the electron spin as an additional degree of freedom but still relies on electron motion in the form of electrical spin currents.
The spin-wave quasiparticle, known as a magnon, flows and carries spin angular momentum in much the same way that electrons do. In a well-prepared sample, it can propagate as far as centimeters—three orders of magnitude...
