Phase evolution, structure, and magnetic properties of Nd8.4Fe86Mo1.1B4.5 nanocomposite magnets

The relationship between the phase evolution, nanostructure, exchange coupling, and magnetic properties of Nd8.4Fe86Mo1.1B4.5 magnets prepared by melt spinning (MS) and mechanical milling (MM) are studied by x-ray diffraction, Mossbauer spectroscopy, positron lifetime measurements, high resolution transmission electron microscopy observations, and magnetization measurements. The maximum magnetic energy product (BH)(max) for MM magnets annealed at 650 degreesC or below are notably higher than those of the corresponding MS samples due to the larger amount of the Nd(Fe,Mo)(7) present in the MS samples. (C) 2002 American Institute of Physics.