C. Wittwer et al., DYNAMIC LOSSES IN NANOCRYSTALLINE FINEMET FOR VARIOUS ANNEALING TEMPERATURE, Journal of magnetism and magnetic materials, 133(1-3), 1994, pp. 287-290
The influence of thermal treatments on the dynamical magnetic properti
es of finemet ribbons was investigated. The amorphous ribbons of compo
sition Fe73.5Cu1Nb3Si13.5B9 have been annealed at various temperatures
. Above their crystallization temperature homogenous, nanocrystalline
of-FeSi grains with grain diameter of 3-12 nm have been produced. The
total energy loss density for frequencies from 20 Hz to 50 kHz and pol
arizations from 0.2 to 0.9 T was measured and subdivided into hysteres
is loss and dynamic loss. For annealing temperatures from 500 to 580-d
egrees-C and 1 h annealing time a broad minimum in the hysteresis loss
es occurs and splitting up into two minima for high polarizations. The
dynamic losses show deeper minima at nearly the same annealing temper
atures. The total losses in the region of the broad minimum of the hys
teresis losses are mainly determined by the dynamic losses. For anneal
ing temperatures over 590-degrees-C the total losses are mainly determ
ined by the hysteresis losses. For 0.2 T polarization amplitude and hi
gh frequencies the decrease of the anomaly factor with increasing freq
uency is extraordinarily high.