Iron Loss of Supermalloy Film Core

The suitability of a supermalloy thin film about 1 μm thick for use in 1 MHz power equipment was studied. The relationship between the hysteresis loss W
_h
and the maximum flux density B
_m
for the approximately 1 μm thick films deposited on SiO
₂
substrate is approximately W
_h
∝ B
_m
^1.75
. This shows the same tendency as that for the rolled plate, where W
_h
∝ B
_m
^1.6
, but the hysteresis loss value is one order of magnitude greater. In conventional rolled tape, the hysteresis loss is inversely proportional to tape thickness, but in the case of thin films, W
_h
obstructs any large-scale reduction in the loss.