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arXiv · 2112.05961

Optical excitation of electromagnons in hexaferrite

Hiroki Ueda·Hoyoung Jang·Sae Hwan Chun·Hyeong-Do Kim·Minseok Kim·Sang-Youn Park·Simone Finizio·Nazaret Ortiz Hernandez·Vladimir Ovuka·Matteo Savoini·Tsuyoshi Kimura·Yoshikazu Tanaka·Andrin Doll·Urs Staub
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Abstract

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.

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Hiroki Ueda, Hoyoung Jang, Sae Hwan Chun, Hyeong-Do Kim, Minseok Kim, Sang-Youn Park, Simone Finizio, Nazaret Ortiz Hernandez, Vladimir Ovuka, Matteo Savoini, Tsuyoshi Kimura, Yoshikazu Tanaka, Andrin Doll, Urs Staub. 2021-12-11. Optical excitation of electromagnons in hexaferrite. https://doi.org/10.1103/physrevresearch.4.023007

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