Understanding ultrafast magnetization dynamics on the microscopic level is of strong current interest due to the potential for applications in information storage. In recent years, the spin-lattice coupling has been recognized to be essential for ultrafast magnetization dynamics. Magnetoelectric multiferroics of type II possess intrinsic correlations among magnetic sublattices and electric polarization (P) through spin-lattice coupling, enabling fundamentally coupled dynamics between spins and lattice. Here we report on ultrafast magnetization dynamics in a room-temperature multiferroic hexaferrite possessing ferrimagnetic and antiferromagnetic sublattices, revealed by time-resolved resonant x-ray diffraction. A femtosecond above-bandgap excitation triggers a coherent magnon in which the two magnetic sublattices entangle and give rise to a transient modulation of P. A novel microscopic mechanism for triggering the coherent magnon in this ferrimagnetic insulator based on the spin-lattice coupling is proposed. Our finding opens up a novel but general pathway for ultrafast control of magnetism.
@article{arxiv.2112.05961,
title = {Optical excitation of electromagnons in hexaferrite},
author = {Hiroki Ueda and Hoyoung Jang and Sae Hwan Chun and Hyeong-Do Kim and Minseok Kim and Sang-Youn Park and Simone Finizio and Nazaret Ortiz Hernandez and Vladimir Ovuka and Matteo Savoini and Tsuyoshi Kimura and Yoshikazu Tanaka and Andrin Doll and Urs Staub},
journal= {arXiv preprint arXiv:2112.05961},
year = {2022}
}
Comments
18 pages, 7 figures + 21 pages supplementary information