American Physical Society October 26, 2020
A magnon polaron, hybridized state of a phonon and a magnon, can be formed at the intersection of the magnon and phonon dispersions, where their frequencies coincide. However, the weak interaction of magnons and phonons and their short lifetimes jeopardize the strong coupling required for the formation of a hybridized state. An international team of researchers (Germany, Russia, Ukraine, UK) overcame these limitations by spatial matching of magnons and phonons in a metallic ferromagnet with a nanoscale periodic surface pattern. The spatial overlap results in a high coupling strength which, in combination with their long lifetimes, allowed them to find clear evidence of an optically excited magnon polaron. They showed that the symmetries of the localized magnon and phonon states play a crucial role in the magnon polaron formation and its manifestation in the optically excited magnetic transients. According to the researchers their structure is better suited for applications in integrated optoelectronic circuits…read more. TECHNICAL ARTICLE
In a nanopatterned magnetic structure illuminated by a short laser pulse, magnons and photons couple to form quasiparticles called magnon-polarons.