Abstract:

In this work we use thermal analysis methods, X-ray diffraction and magnetization measurements to carry out a systematic study on amorphous magnetic materials. In this sense, as-quenched amorphous samples of Ni40Fe40P14B6 and Fe76,5Cu1 Nb3Si13,5B6 were used. We have interpreted the crystallization kinetics in terms of the Johnson/Mehl/Avrami (JMA) nucleation-growth model. X-ray diffraction data as function of temperature reveal that our samples consist of single phases of Fe-rich nanocrystals embedded in a residual amorphous phase. Magnetic measurements as function of temperature show a sharp decreases of the magnetization around 200 and 3500C to Ni40Fe40P14B6 and Fe76,5Cu1 Nb3Si13,5B6, respectively, likely related to the Curie temperatures. TGA and magnetization curves show additional increases in the high temperature region which are attributed to the growth of the Fe-rich magnetic phases.