Observation of mode splitting by magnon-magnon coupling in synthetic antiferromagnets

We investigated the coherently excited propagating magnons in in-plane magnetized synthetic antiferromagnets using heterodyne-magnetooptical Kerr effect technique. Under the in-plane magnetic field to 45 degrees away from the magnon propagation direction, we observed the mode splitting of magnon dispersion relation due to the magnon-magnon coupling between acoustic and optical magnon modes. The strong coupling with a cooperativity of 8.4 +/- 1.3 is achieved for finite wavenumber. These results provide a deep understanding of the properties of coherently excited magnons in synthetic antiferromagnets, which will be helpful for designing advanced magnonic devices. (c) 2023 The Japan Society of Applied Physics

Automated summary

We investigated the coherently excited propagating magnons in in-plane magnetized synthetic antiferromagnets using heterodyne-magnetooptical Kerr effect technique. Under an in-plane magnetic field at a 45-degree angle away from the magnon propagation direction, we observed mode splitting of the magnon dispersion relation due to magnon-magnon coupling between acoustic and optical magnon modes. Strong coupling with a cooperativity of 8.4 +/- 1.3 was achieved for finite wavenumber. These results provide a deep understanding of the properties of coherently excited magnons in synthetic antiferromagnets, which will be helpful for designing advanced magnonic devices.