Spin Wave in MnF2 (IMAGE) Max-Planck-Gesellschaft Caption A "snapshot" of a spin wave in the antiferromagnet MnF2. The basic unit of the MnF2 crystal is depicted: the gray spheres represent Mn2+ ions and the green spheres F- ions. A spin (thick black arrows) is associated with each Mn2+ ion. Those at the corners of the cell point approximately in the opposite direction from that at the center. In a spin-wave excitation, the spins may be considered to precess around cones (shown here in blue). In the experiment reported here, the lifetime of long-lived spin waves was measured over a broad range of momenta. Credit Max Planck Institute for Solid State Physics Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.