Effects of anisotropy on domain structures in amorphous ribbons

Using SEM techniques, magnetic domains have been studied in amorphous ribbons of Co
70.3
Fe
4.7
Si
15
B
10
annealed to produce different values of transverse anisotropy constant K
u
. The average domain width varied as K
u
^-1/6
, in agreement with theoretical models incorporating the μ-effect. Domains were also studied in ribbons annealed to produce a transition from longitudinal to transverse anisotropy. Ribbons with very low transverse K
u
contain coarse and irregular domains whose widths vary with time and magnetic history. Maximum initial permeability occurs not at zero net anisotropy, but at low values of transverse anisotropy.