Superparamagnetism in the devitrification of amorphousNi80B20

The detection and study of the superparamagnetic behavior of the melt-spun amorphous ${\mathrm{Ni}}_{80}{\mathrm{B}}_{20}$ at different stages before and during its devitrification has shed light on the controversial topic of the crystallization mechanisms involved in the process. The results are consistent with the annealing temperature dependence of the Curie temperature and the x-ray-diffraction pattern, allowing us to conclude that the growth of the Ni-rich nanocrystallites nucleated at the temperature signaled by the first differential scanning calorimeter exothermic peak does not take place until most of the remaining boron has been segregated.