Transmission electron microscopy has been used to study the magnetic a
nd physical microstructure bf thinned samples of NdFeB. Various compos
itions of sintered material and nanocrystalline melt-spun ribbon have
been studied The mean grain size in the materials ranges from 3 mu m i
n the sintered material down to 20 nm in the ribbon and this has a pro
nounced effect on the domain structures supported. Details of the magn
etisation distribution both within grains and around boundaries are gi
ven and these are discussed in terms of the observed bulk magnetic pro
perties.