  Magnetization dynamics triggered with ultrashort laser pulses has been
attracting significant attention, with strong focus on the dynamics excited by
VIS/NIR pulses. Only recently, strong magnetic response in solid materials
induced by intense X-ray pulses from free-electron lasers (FELs) has been
observed. The exact mechanisms that trigger the X-ray induced demagnetization
are not yet fully understood. They are subject of on-going experimental and
theoretical investigations. Here, we present a theoretical analysis of
electronic processes occurring during demagnetization of Co multilayer system
irradiated by X-ray pulses tuned to L$_3$-absorption edge of cobalt. We show
that, similarly as in the case of X-ray induced demagnetization at M-edge of
Co, electronic processes play a predominant role in the demagnetization until
the pulse fluence does not exceed the structural damage threshold. The impact
of electronic processes can reasonably well explain the available experimental
data, without a need to introduce the mechanism of stimulated elastic forward
scattering.
