INVESTIGATION OF MAGNETIC PROPERTIES IN IRON-BASED NANOCRYSTALLINE ALLOYS BY MOESSBAUER EFFECT AND MAGNETIZATION MEASUREMENTS

摘要

The combination of Moessbauer effect spectrometry and magnetization measurements delivers a founded and new insight in the properties of modern nanostructured materials. We presented investigations on alloys exhibiting bcc-Fe nanograins embedded in an amorphous matrix gained by suitable annealing of amorphous Fe_(79)Cu_1Nb_7B_(13) alloys. Moessbauer spectrometry and TEM delivered a direct measure about the concentration of the nanograins. The very characteristic shape of the spectral lines of the bcc-Fe spectral component is a mark for particle-particle interaction and was evaluated using a new idea of relaxation spectra. Magnetization measurements and Moessbauer spectrometry delivered evidence for super-paramagnetic behaviour at low nanograin concentrations. At higher nanograin concentrations the particle-particle interaction leads to a collective magnetic behaviour: to the (by the external field) forced super-ferromagnetism.