Nanoscale transient magnetization gratings excited and probed by femtosecond extreme ultraviolet pulses

Abstract

We utilize coherent femtosecond extreme ultraviolet (EUV) pulses derived from a free electron laser (FEL) to generate transient periodic magnetization patterns with periods as short as 44 nm. Combining spatially periodic excitation with resonant probing at the dichroic M-edge of cobalt allows us to create and probe transient gratings of electronic and magnetic excitations in a CoGd alloy. In a demagnetized sample, we observe an electronic excitation with 50 fs rise time close to the FEL pulse duration and ~0.5 ps decay time within the range for the electron-phonon relaxation in metals. When the experiment is performed on a sample magnetized to saturation in an external field, we observe a magnetization grating, which appears on a sub-picosecond time scale as the sample is demagnetized at the maxima of the EUV intensity and then decays on the time scale of tens of picoseconds via thermal diffusion. The described approach opens prospects for studying dynamics of ultrafast magnetic phenomena on nanometer length scales.

References in corpus (3)

• Super-Diffusive Spin-Transport as a Mechanism of Ultrafast Demagnetization
• Direct Measurement of Room Temperature Non-diffusive Thermal Transport Over Micron Distances in a Silicon Membrane
• Coherent Propagation of Spin Helices in a Quantum-Well Confined Electron Gas

Cited by in corpus (10)

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• Pseudo-spectral Landau-Lifshitz description of magnetization dynamics
• Transient grating spectroscopy on a DyCo${}_5$ thin film with femtosecond extreme ultraviolet pulses
• Magnetization precession after non-collinear dual optical excitation
• Steering light with magnetic textures
• Spin waves excited by hard x-ray transient gratings