Materials, physics, and devices of magnonics

In 1930, Bloch 1 proposed that when the magnetic moment in a magnetic system is disturbed, it deviates from equilibrium states.Such disturbances will propagate through the material in the form of waves, known as spin waves.Later in 1957, Brockhouse 2 confirmed the existence of spin waves through neutron diffraction experiments, and the quantized units of spin waves are called magnons.Magnons, as the elementary excitations in magnetic systems, have several advantages: they propagate without generating Joule heat, exhibit wave characteristics, have intrinsic frequencies ranging from gigahertz to terahertz, and support a rich set of techniques for exciting, manipulating, and detecting their transport.Therefore, they are poised as a potential candidate to replace electrons as the carriers for the next-generation information technology.In recent years, due to advancements in research techniques for magnons, the study of magnons has attracted increasing attention.Thanks to the organization by the Editorial Board of Applied Physics Letters, we are honored to organize a special issue on the topic of Magnonics.Focusing on materials, physics, and devices related to magnonics, 3 we accepted and published a total of 55 papers.This special topic issue was proposed in Applied Physics Letters to draw more interest to this emerging field.It includes cutting-edge research in magnonics across various directions: