Element- and Site-Specific Phonon Density of States Measured by Nuclear Resonant Inelastic Scattering of Synchrotron Radiation

Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494
â—‹Makoto SETO

Oscillating properties of the individual atoms in non-equivalent positions in a compound are not necessarily equivalent. Since it is well known that the dynamics of certain atoms in a compound influence the characteristics, to obtain the information on each atomic motion is important. The nuclear resonant inelastic scattering of synchrotron radiation offers element-specific phonon energy spectra. Therefore, it has been applied to a wide variety of scientific fields. In the case of a compound with two or more different states of atoms of the same element, such as mixed Fe valent magnetite, it is very difficult to observe the site-specific phonon densities of states (PDOS) experimentally. However, the combination of the energy and time domain measurements of the nuclear resonant scattering permits the observation of site-specific PDOS. We could measure the site-specific PDOS of Fe atoms in magnetite using nuclear resonant scattering of synchrotron radiation, and this result opened new area of a research. The principal concepts and the experimental results are discussed.