Optical excitation of electromagnons in hexaferrite

Ueda, Hirokazu; Jang, Hoyoung; Chun, Sae Hwan; Kim, Hyeong–Do; Kim, Minseok; Park, Sang‐Youn; Finizio, Simone; Hernández, Nazaret Ortiz; Ovuka, Vladimir; Savoini, Matteo; Kimura, T.; Tanaka, Yoshikazu; Doll, Andrin; Staub, U.

doi:10.1103/physrevresearch.4.023007

Cited by 6 publications

(9 citation statements)

References 47 publications

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“…1-c. The results for the AFM component display an ultrafast demagnetization (resolution limited, τ = 220 fs) followed by a 53.2 ± 0.8 GHz oscillation indicative of the coherent excitation of a magnon, in agreement with previous published results [9]. Using the full polarization control of the Apple X undulator, we can directly investigate the time evolution of the FM magnetization M, which can be probed by circular dichroic TR-RXRD measurements.…”

Section: Furka Endstation First Commissioning Resultssupporting

confidence: 89%

“…Such a magnetoelectric coupling is a promising pathway for ultrafast control of magnetism [8]. In SCFO, two electromagnon modes exist, which are hybrid modes of magnons and polar phonons [9,10]. The previous study reported that an above-bandgap optical excitation can excite the slower electromagnon, which is observed as oscillations in the corresponding diffraction peak intensities.…”

Section: Furka Endstation First Commissioning Resultsmentioning

confidence: 99%

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Ultrafast dynamics in quantum matter at SwissFEL: capabilities of Furka endstation

Razzoli

Ueda

Paris

et al. 2023

X-Ray Free-Electron Lasers: Advances in Source Development and Instrumentation VI

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Time-resolved spectroscopies have provided insights in the quest for understanding the fundamental properties of quantum materials and towards controlling their functional properties through light-matter interaction. In this regard, Free Electrons Lasers (FELs) have developed as a powerful tool to perform ultrafast x-ray spectroscopy to obtain energy and momentum-resolved information. In this contribution, we introduce the SwissFEL soft-x-ray condensed matter experimental endstation, named Furka, which is dedicated to Time-Resolved X-ray Absorption (TR-XAS), resonant X-Ray Diffraction (TR-RXRD) and Resonant Inelastic x-ray Scattering (TR-RIXS) experiments to study quantum materials. The current status of the endstation and the first results from the commissioning phase will also be discussed.

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Section: Furka Endstation First Commissioning Resultssupporting

confidence: 89%

Section: Furka Endstation First Commissioning Resultsmentioning

confidence: 99%

Ultrafast dynamics in quantum matter at SwissFEL: capabilities of Furka endstation

Razzoli

Ueda

Paris

et al. 2023

X-Ray Free-Electron Lasers: Advances in Source Development and Instrumentation VI

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“…We remark that the overall fluence dependence in Fig. 4c is in stark contrast with that for the coherent magnon driven by photoinduced strain on lattice 30,32,33,48 . The photoexcitation above and below the band gap are able to produce the strain through one-photon and twophoton absorption processes, respectively.…”

Section: Photoinduced Magnetic-fieldmentioning

confidence: 70%

“…We find a remarkable amplification of the photomagnetic effect by the above-band-gap photoexcitation, which exhibits substantial field of 187 mT with the laser fluence of 1.0 mJ/cm 2 in contrast to 12.3 mT for the below-band-gap photoexcitation. This observation underscores a highly energy-efficient route to achieve substantial photoinduced fields desired for optospintronics applications 31 , which has been obscured with other photoinduced strain 30,32,33 or heating effects 4 . The scope of the applications even broadens for multiferroics with magnetic and electric dipoles strongly coupled to each other, with the notion that the optical manipulation of a magnetic moment will be also functional for controlling the ferroelectric polarization, and vice versa 26,34,35 .…”

Section: Magnetism Maneuverable By An Ultrashort Optical Laser Pulse ...mentioning

confidence: 97%

“…The recent development of X-ray free electron lasers (XFELs) has made a breakthrough extending various X-ray spectroscopy and scattering techniques into the ultrafast time domain using ultrashort femtosecond X-ray pulses with high brightness 24 . In particular, this applies to resonant magnetic X-ray diffraction which can selectively probe FM or AFM order parameters [25][26][27][28][29][30] and thereby be applicable for every class of magnets. The resonant X-ray scattering process poses distinct X-ray polarization channels on which the individual components of the magnetic moments projected, differently contribute to the selected magnetic Bragg peaks.…”

Section: Magnetism Maneuverable By An Ultrashort Optical Laser Pulse ...mentioning

confidence: 99%

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4D visualization of the light-induced coherent magnon by an X-ray free electron laser

Jang

Ueda

Kim

et al. 2022

Preprint

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Ultrafast optical manipulation of magnetic phenomena is an exciting achievement of mankind, expanding one’s horizon of knowledge towards functional non-equilibrium states. The dynamics acting on an extremely short timescale push the limit of detection, and ultimately require four-dimensional (4D) views, i.e., 3D space and 1D time to keep sight of the evolving magnetic structure thoroughly. Here we introduce time-resolved resonant magnetic X-ray diffraction with an X-ray free electron laser to accomplish the 4D visualization of a light-induced coherent magnon. The trajectory of antiferromagnetic precession in a Y-type hexaferrite manifests a photoinduced effective magnetic-field that lasts long after the photoirradiation, being attributed to nonthermal inter-site electron transfer among the magnetic ions. With the unprecedented capability of direct quantifying the field for the photoexcitation above the band gap, we find a remarkable amplification of the photomagnetic effect reaching an order of magnitude higher than that below the gap with the same laser fluence. This result illuminates a highly energy-efficient route to achieve substantial photoinduced field in antiferromagnetic dielectrics desired for optospintronics applications. The X-ray methodology established in this work has no restriction on net-magnetization, offering a great capability to uncover ultrafast magnetic phenomena in every class of magnets.

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

et al. 2023

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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.

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Optical excitation of electromagnons in hexaferrite

Cited by 6 publications

References 47 publications

Ultrafast dynamics in quantum matter at SwissFEL: capabilities of Furka endstation

Ultrafast dynamics in quantum matter at SwissFEL: capabilities of Furka endstation

4D visualization of the light-induced coherent magnon by an X-ray free electron laser

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

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