Papers by Renaud Delaunay
The Journal of Physical Chemistry C
Journal of Synchrotron Radiation
The SOLEIL synchrotron radiation source is regularly operated in special filling modes dedicated ... more The SOLEIL synchrotron radiation source is regularly operated in special filling modes dedicated to pump–probe experiments. Among others, the low-α mode operation is characterized by shorter pulse duration and represents the natural bridge between 50 ps synchrotron pulses and femtosecond experiments. Here, the capabilities in low-α mode of the experimental set-ups developed at the TEMPO beamline to perform pump–probe experiments with soft X-rays based on photoelectron or photon detection are presented. A 282 kHz repetition-rate femtosecond laser is synchronized with the synchrotron radiation time structure to induce fast electronic and/or magnetic excitations. Detection is performed using a two-dimensional space resolution plus time resolution detector based on microchannel plates equipped with a delay line. Results of time-resolved photoelectron spectroscopy, circular dichroism and magnetic scattering experiments are reported, and their respective advantages and limitations in the ...
Journal of Physics D: Applied Physics, 2016
Nature Communications, 2016
Scientific reports, Jan 6, 2016
Does the excitation of ultrafast magnetization require direct interaction between the photons of ... more Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a negligible number of IR photons penetrate the aluminum layer. In comparison with an uncapped cobalt/palladium reference film, the initial demagnetization of the capped film occurs with a delayed onset and at a slower rate. Both observations are qualitatively in line with energy transport from the aluminum layer into the underlying magnetic film by the excited, hot electrons of the aluminum film. Our data thus confirm recent theoretical predictions.
Surface Review and Letters, 2002
By simultaneous measurements of sample resistance and of X-ray resonant scattering, we tried to e... more By simultaneous measurements of sample resistance and of X-ray resonant scattering, we tried to establish a direct correlation between magnetoresistance (MR) and antiferromagnetic (AF) order in a Co/Cu metallic multilayer. Field-dependent scattered intensity has been measured in a geometrical configuration corresponding to the Bragg peak coming from the AF coupling, at a photon energy close to the Co L 3 absorption edge (hν = 776.5 eV ). The comparison between measurements of the scattered intensity and of the resistance clearly shows a direct correlation between AF order and MR.
Surface Review and Letters, 2002
The impact of resonant scattering of polarized X-rays is illustrated taking the gadolinium 4d edg... more The impact of resonant scattering of polarized X-rays is illustrated taking the gadolinium 4d edge energy range as an example. It is shown that: (i) the study of the reflection of linearly polarized light by a magnetized Gd sample gives information on the electronic states of the system, similar to that given by magnetic circular dichroism in absorption; (ii) the energy-loss peaks corresponding to spin-flip transitions in the 4d → 4f excitation exhibit a strong circular dichroism.
Solid State Communications, 2005
Review of Scientific Instruments, 2009
Physical Review Letters, 2004
Physical Review Letters, 2012
Physica B: Condensed Matter, 1995
Physica B: Condensed Matter, 1995
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Papers by Renaud Delaunay