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Updated: May 17, 2026
10:52
Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Spin Waves Excited by Hard X-Ray Transient Gratings
Peter R Miedaner1, Alexei A Maznev1, Mykola Biednov2
1Massachusetts Institute of Technology, Department of Chemistry, Cambridge, Massachusetts, USA.
Physical Review Letters
|May 15, 2026
Summary
Ultrafast hard x-rays can drive magnetic dynamics in ferrimagnetic films. This study demonstrates x-ray transient gratings for exciting coherent phonons and magnons, enabling wave vector exploration.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Ultrafast Science
Background:
- Ultrafast x-ray sources enable probing lattice and magnetic dynamics.
- Femtosecond optical pulses initiate material excitations.
- Hard x-rays offer potential for driving magnetic dynamics.
Purpose of the Study:
- Explore ultrashort hard x-ray pulses for driving magnetic dynamics.
- Utilize the x-ray transient grating technique for material excitation.
- Monitor dynamics via optical probe pulse diffraction.
Main Methods:
- Employing a transient grating technique with spatially periodic x-ray excitation.
- Exciting a ferrimagnetic gadolinium bismuth iron garnet film.
- Separating magnetic and nonmagnetic grating contributions using polarization analysis.
Main Results:
- Observed magnetization precession at longitudinal acoustic and spin wave frequencies.
- Identified strain from x-ray-induced thermal expansion as the driver of precession.
- Demonstrated separation of magnetic and nonmagnetic transient gratings.
Conclusions:
- Established x-ray transient gratings as a method for driving coherent phonons and magnons.
- Showcased the potential for accessing wave vectors across the entire Brillouin zone.
- Highlighted x-rays as a tool for initiating and probing ultrafast dynamics.
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