S. Sabolek et al., EFFECTS OF TORSION ON THE DECREASE OF LOSS BY MEANS OF CORE CURRENT IN FE80B20 AMORPHOUS RIBBON, Physica status solidi. a, Applied research, 148(1), 1995, pp. 283-293
The effects of torsion (specific twist tau = 0, 5, 10, 15, 20, and 30
pi/m) on the domains and pinning in an as-quenched Fe80B20 amorphous r
ibbon are studied by means of the direct (J(D)) and alternating (J) co
re currents. For all twist angles and both J and J(D) the model of the
influence of the surface field H-p generated by the core current on t
he magnetization of amorphous ribbons describes well the observed dM/d
t versus H curves and the corresponding M-H loops. The analysis of the
effects of H-p on the coercive field H-c and the shift of the center
C of the M-H loop shows that torsion increases both the average angle
[delta] between the domain magnetizations (I) and the ribbon axis and
the pinning of the domain walls. The competition between these effects
results in an optimum tau approximate to 10 pi/m for which H-c = 0 is
obtained with the lowest amplitude J(0) of J. An explanation of these
phenomena in terms of the appearance of an easy axis of magnetization
and the increase in stresses due to torsion (tau) is provided.