Influence of Magnetic Field Annealing Methods on Soft Magnetic Properties for FeCo-Based Nanocrystalline Alloys

The influence of magnetic field annealing methods on soft magnetic properties was investigated by measuring initial permeability
$\mu _{i}$
, saturation magnetostriction
$\lambda _{s}$
, and effective magnetic anisotropy
$\langle K\rangle $
of nanocrystalline (Fe
_1–x
Co
_x
)
_73.5
Si
_13.5
B
₉
Nb
₃
Cu
₁
(
$x=0.25$
, 0.5, and 0.75) alloys under different magnetic field thermal treatments. Compared with nonmagnetic field annealing, three magnetic field annealing methods can increase the
$\mu _{i}$
of FeCo-based experimental samples, but the impact degree is significantly different. After magnetic field annealing,
$\lambda _{s}$
was reduced and
$\langle K\rangle $
was enhanced, which can contribute to the increase of
$\mu _{i}$
. By comparing three magnetic field annealing methods, we found that the magnetic field nanocrystallization is the most effective magnetic field annealing method to improve the magnetic softness of samples, which could be attributed to a stronger ferromagnetic atomic mobility in the early period of primary crystallization.