Mossbauer study of defects and local structure in solids

Fe-57 Mossbauer study of the point defects induced by electron beam irradia tion in aluminum containing 100 ppm of Fe-57 impurities has been presented. Fe-57 Mossbauer spectra obtained at 10 K just after the electron irradiati on at 77 K show satellite lines rising from the defects associated with the Fe-57 probe atoms in aluminum matrix. The intensity of the satellite line (defect line) abruptly diminished around 20 K. Apparent reduction in the in tensity of the defect line is interpreted as a result of the local jump of the probe Fe-57 atoms in the cage, which consists of six geometrically equi valent mixed-dumbbell positions. The local jump collapses the coherence of the Mossbauer gamma-rays and the lime dependent relaxation of the quadrupol e interaction occurs.