MOSSBAUER-SPECTROSCOPY TO INVESTIGATE JUMP MECHANISMS ON ANATOMIC SCALE - FAST DIFFUSION STUDIES

The fast diffusion of transition-metal impurities in metals and semico nductors provides us with a challenging research field, because the ju mp frequencies and the concentration of the ''diffusion vehicles'' (pr obably interstitials) contributing to the fast diffusion are always cl ose to the detection limit of Mossbauer spectroscopy. Therefore, sever al new experimental set-ups have to be developed in order to achieve a direct observation of the fast diffusing vehicles and to study the ju mp mechanism on an atomic scale. High temperature UHV-furnaces and the in-beam Mossbauer spectrometers, which have been constructed in diffe rent institutes in different countries, are introduced and the new exp erimental results obtained by these apparatus are presented.