THE TEMPERATURE RELATIONSHIP OF THE FLUCTUATION FIELD AND COERCIVITY IN NDFEB ALLOYS

The coercivity H(c) and fluctuation field H(f) are intrinsic properties of any magnetic system exhibiting hysteresis. They are measures of the energy barriers resisting magnetization reversal and may be used to probe the nature of the magnetization processes. The variation of coercivity as a function of temperature and of the fluctuation field as a function of field and temperature have been studied for sintered and melt-spun NdFeB. The fluctuation field has been found to vary with field in the sintered material indicating that interactions play an important role in the nucleation of reverse domains while it remained constant in the melt-spun sample. The relationship between the coercivity and fluctuation field has been studied and found to be consistent with the Barbier plot though some deviation from the expected curve was found.