Fig. 4-15 Conceptual figures of element-specific nuclear resonant excitation and inelastic nuclear resonant scattering spectrum It is known that an incident x-ray photon changes its energy slightly due to the influence of the vibration of the lattice in the target material. Therefore, if we measure the intensity of inelastic nuclear resonant scattering with an energy scan near the resonant energy of the specific atom, the measured spectra show the peak intensity or the line broadening according to phonon annihilation and creations. <<inelastic (Quasi-elastic) nuclear resonant scattering>> These spectra provide us the information on vibration of the lattice of the specific atom in the material.

Fig. 4-16 Inelastic nuclear resonant scattering spectra of FeCl3-GIC In the case of incident x-rays perpendicular to the graphite layers, a high energy phonon mode (around 10 MeV) contributes to the nuclear resonant scattering much more than for the parallel case.

The study of electron-lattice interaction in solid material is very important for the investigations of structural phase transitions or superconducting phenomena etc. Presently, in SPring-8 (third generation synchrotron radiation), we perform studies on the lattice dynamics and diffusion phenomena of solid material by using the inelastic nuclear resonant scattering method. The measurement of an inelastic nuclear resonant scattering spectrum facilitates the study of the phonon density of state marked by the specific atom (Fig. 4-15). As an example, the behavior of the iron atom in graphite intercalation compounds (GIC) was investigated. The inelastic nuclear resonant scattering spectra of FeCl3-GIC are shown in Fig. 4-16. These spectra are measured in both cases of incident x-rays perpendicular and parallel to the FeCl3-GIC layers. As a result, it is proved that 57Fe doesn't move easily in the direction perpendicular to the layers as compared with the parallel direction.

Reference S. Kitao et al., Inelastic Nuclear Resonant Scattering of FeCl3-Graphite Intercalation Compounds, Jpn. J. Appl. Phys., 38(1), 535 (1999).

Select a topic in left column