Magyar Tudományos Akadémia
S. N. Kane
Backscattering Mossbauer spectroscopy (Miniaturized Mossbauer spectrometer-MIMOS) applied in investigation of new nanocrystalline alloys
Depth selective crystallization of CoxFe84-xNb7B9 (x = 17, 25 and 33) alloys induced by thermal annealing has been studied using 6.4 and 14.4 keV backscattered and 14.4 keV transmission Mössbauer spectroscopy. It is shown that Mössbauer spectroscopy in backscattering and transmission geometry can be effectively used to detect changes in the environment around Fe-atom (boron or niobium near neighbour to the Fe-atom), differences in Co content on surface and the bulk of the specimen and relative fraction of Fe-atoms in the crystalline phase as a function of depth of the specimen which in-turn should have an effect on the magnetic properties of the studied nanocrystalline materials. Lattice parameter and the hyperfine field of the crystalline component show that the crystallization leads to the formation of Fe-rich Fe-Co phase (Fe ranging between 89 to 96 % and Co ranging between 4 to 11 %) and the composition of the crystalline component at the surface and the bulk is different.
Devoted to extraterrestrial applications of MIMOS. Representative results obtained at ‘planet MARS’ (in the framework of NASA’s Mars Exploration Rover (MER) program) will be presented.
2004. augusztus 17. (kedd) de. 10:00
I. épület Tanácsterem
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