Optical excitation of electromagnons in hexaferrite

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.

18 pages, 7 figures + 21 pages supplementary information

References in corpus (7)

• Ultrafast photo-magnetic recording in transparent medium
• Ultrafast phononic switching of magnetization
• Magnetization-polarization cross-control near room temperature in hexaferrite single crystals
• Detection of coherent magnons via ultrafast pump-probe reflectance spectroscopy in multiferroic Ba0.6Sr1.4Zn2Fe12O22
• Electromagnon in the Z-type hexaferrite $({\mathrm{Ba}}_x{\mathrm{Sr}}_{1-x}{)}_3\mathrm{C}{\mathrm{o}}_2\mathrm{F}{\mathrm{e}}_{24}{\mathrm{O}}_{41}$
• Observation of magnetic domain and bubble structures in magnetoelectric Sr${}_3$Co${}_2$Fe${}_{24}$O${}_{41}$
• Time-resolved resonant elastic soft X-ray scattering at Pohang Accelerator Laboratory X-ray Free Electron Laser

Cited by in corpus (2)

• Non-equilibrium dynamics of spin-lattice coupling
• 4D visualization of the photoexcited coherent magnon by an X-ray free electron laser