Experimental results in ball-milled nanocrystalline Fe, Fe(Si) and Ni(Fe) alloys,
based on our measurements of the temperature dependence of magnetization, Barkhausen-noise,
hysteresis loops and Mössbauer-effect are reviewed and compared with results of measurements
obtained on nanocrystalline samples produced by other techniques.
It has been shown that the intrinsic magnetic properties (the saturation magnetization
(Ms), the hyperfine magnetic field in the Mössbauer spectra, and the Curie-temperature
(Tc)) are almost independent of the grain size (d) down to about 6 nm. This is in
accordance with the newest experimental results obtained on nanocrystalline Fe produced
by inert gas evaporation  and on Ni produced by severe plastic deformation consolidation
of ball-milled powders  and by electrodeposition .
The grain size dependence of coercivity (Hc) has been found to be similar to what
can be expected from the classical and random anisotropy model. The differences observed
between the Hc vs grain size curves can be explained by different sample preparation
techniques and to different materials.
A definite correlation between the magnetic Barkhausen-noise (MBN) and the grain shape
has been found in Fe which can be attributed to the formation of lamellar and textured
grain structure. In Ni -- where no texture formation was observed -- there was a maximum
on the MBN curve versus grain size at the same d where the sharp drop in Hc at small
d values was obtained. Furthermore it was also shown -- by the separation of the effect
of grain size and the residual strain (by relaxing it in an appropriate heat treatment)
-- that in nanocrystalline Ni the coercivity is practically independent of the residual