Resonant magnetic scattering with soft x-ray pulses from a free-electron laser operating at 1.59 nm

We report on a resonant magnetic scattering experiment using soft x-ray pulses generated from a free-electron laser (FEL). The free-electron laser was operated at a fundamental wavelength of 7.97 nm and radiation at the fifth harmonic originating from self-amplified stimulated emission at 1.59 nm with an average energy of 4 nJ per pulse was detected. We demonstrate the feasibility of resonant magnetic scattering at FEL sources by using a Co/Pd multilayer as prototype sample that was illuminated with 20-fs-long soft x-ray pulses tuned to the $\text{Co}{L}_3$ absorption edge at 778.1 eV (1.59 nm).

Figure 1

(Color online) Scheme of the experimental setup.

Figure 2

(Color online) The curves show profiles of the direct beam of FLASH at the fifth harmonic with the SASE process switched on and off (see text for details).

Figure 3

(Color online) Top: CCD image of the magnetic diffraction pattern recorded with soft x-ray SASE laser radiation at a wavelength of 1.59 nm ($\text{Co}{L}_3$ edge, photon energy of 778.1 eV). The color bar indicates the number of photons recorded per pixel. Bottom: CCD image of the magnetic diffraction pattern recorded with a photon energy of 783.5 eV, slightly off resonance.

Figure 4

(Color online) Azimuthal dependence of the scattering intensity. The asymmetry shows a preferred orientation of the domains—a so-called stripe phase.

Figure 5

(Color online) The curves show the azimuthally integrated magnetic scattering intensity. Red (+): photon energy of 778.1 eV, on resonance at the $\text{Co}{L}_3$ edge. Blue (∗): photon energy of 783.5 eV, slightly off resonance.