TEMPERATURE-DEPENDENCE OF PHONON ENERGY-SPECTRA WITH NUCLEAR RESONANTSCATTERING OF SYNCHROTRON-RADIATION

The phonon energy spectra of a polycrystalline alpha-Fe foil were obse rved at 150 K and 300 K by using the nuclear resonant scattering of sy nchrotron radiation. In each spectrum, inelastic scattering was observ ed at both sides of the elastic peak. It was found that the ratio of t he elastic-scattering component and the asymmetry of the intensity of the side bands observed at 150 K are larger than those observed at 300 K, respectively. The observed temperature-dependent spectra are in go od agreement with the spectra calculated from the phonon energy distri bution function. One of the advantageous features of this method is th at the excitation of only a specific element is possible. Our results show that this method is applicable to the study of lattice dynamics a nd opens a new field of the nuclear resonant scattering spectroscopy.