**Nuclear resonant scattering (NRS)**

NRS by use of synchrotron radiation, is a technique that can be seen as a time-based analogue of Mössbauer spectroscopy. It makes use of a pulsed form of radiation, instead of a continuous source of gamma-radiation like in regular Mössbauer spectroscopy.

It was first observed by Gerdau et al. in Bragg scattering geometry [1].

The radiation pulses will lead to the simultaneous excitation of all possible transitions (hyperfine). During the decay, of the excited states, there will be an emission of multiple quanta. Because the energy levels/states, from which these quanta originate, have similar energies. It will be possible for the quanta to resonate with each other, leading to the creation of a “time spectrum”. This time spectrum shows the “delayed intensity” with respect to the initial excitation moment [1][2].

From this it is possible to, by use of numerical analyse (Fourier transform), gain information about some of the hyperfine parameters like: B_HF (magnetic hyperfine field), QS (quadruple splitting) and IS (isomer shift) [2].

It is important to note that form of the received time spectrum will be dependent on the relative orientation of the k-vector of the incoming radiation beam with respect to the orientation of the magnetic moment in the sample.

If beam and magnetic moment are aligned, it will result in a more simple pattern. While if the beam and the magnetic moment are more and more un-aligned, the paternities of the slope in the time spectrum will be more irregular/complex [2].

[1]

Kai Schlage, Ralf Röhlsberger, Journal of Electron Spectroscopy and Related Phenomena; Nuclear resonant scattering of synchrotron radiation: Applications in magnetism of layered structures; 2013.

[2]

Conference talk by Tomasz Slezak: http://www.hyperfine2016.be/video/32