4D Visualization of a Nonthermal Coherent Magnon in a Laser Heated Lattice by an X-ray Free Electron Laser

Jang, Hoyoung, Ueda, Hiroki, Kim, Hyeong-Do, Kim, Minseok, Shin, Kwang Woo, Kim, Kee Hoon, Park, Sang-Youn, Shin, Hee Jun, Borisov, Pavel, Rosseinsky, Matthew J ORCID: 0000-0002-1910-2483
et al (show 5 more authors) (2023) 4D Visualization of a Nonthermal Coherent Magnon in a Laser Heated Lattice by an X-ray Free Electron Laser. ADVANCED MATERIALS, 35 (36). e2303032-.

Access the full-text of this item by clicking on the Open Access link.


Ultrafast optical manipulation of magnetic phenomena is an exciting achievement of mankind, expanding one's horizon of knowledge toward the functional nonequilibrium states. The dynamics acting on an extremely short timescale push the detection limits that reveal fascinating light-matter interactions for nonthermal creation of effective magnetic fields. While some cases are benchmarked by emergent transient behaviors, otherwise identifying the nonthermal effects remains challenging. Here, a femtosecond time-resolved resonant magnetic X-ray diffraction experiment is introduced, which uses an X-ray free-electron laser (XFEL) to distinguish between the effective field and the photoinduced thermal effect. It is observed that a multiferroic Y-type hexaferrite exhibits magnetic Bragg peak intensity oscillations manifesting entangled antiferromagnetic (AFM) and ferromagnetic (FM) Fourier components of a coherent AFM magnon. The magnon trajectory constructed in 3D space and time domains is decisive to evince ultrafast field formation preceding the lattice thermalization. A remarkable impact of photoexcitation across the electronic bandgap is directly unraveled, amplifying the photomagnetic coupling that is one of the highest among AFM dielectrics. Leveraging the above-bandgap photoexcitation, this energy-efficient optical process further suggests a novel photomagnetic control of ferroelectricity in multiferroics.

Item Type: Article
Uncontrolled Keywords: multiferroic materials, photomagnetic effect, time-resolved resonant magnetic X-ray diffraction, X-ray free electron laser
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 26 Sep 2023 15:53
Last Modified: 01 Oct 2023 10:52
DOI: 10.1002/adma.202303032
Open Access URL: https://doi.org/10.1002/adma.202303032
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3173092