High-pressure studies with nuclear scattering of synchrotron radiation

The nuclear forward scattering (NFS) of synchrotron radiation is especially suited for probing magnetism at high pressure (h.p.), here in the Mbar range, by the nuclear resonances of Fe-57 and Eu-151. We report on high-pressure NFS studies with the 14.4 keV transition of Fe-57, presenting at first the pressure induced alpha-epsilon transformation in iron. Then a systematic study of magnetic RFe2 Laves phases of cubic C15 structure (YFe2, GdFe2) and hexagonal C14 structure (ScFe2, TiFe2) at pressures up to 100 GPa (= 1 Mbar) is given. First, high-pressure NFS studies performed with the 21.5 keV resonance of Eu-151 are also presented, probing valence transitions in EuNi2Ge2 and the magnetism in the CsCl-type h.p. phase of EuTe. Finally, we discuss future applications, such as high-pressure studies of phonon densities of states, using the inelastic channel of nuclear scattering of synchrotron radiation.