Abstract
Magnetic cores with the permeability of approximately 150 were prepared by annealing Metglas 2605S3A ribbons in an O2 or N2 atmosphere, and effect of DC-bias field on their magnetic properties was studied. The atmosphere during annealing did not affect resultant magnetic properties of die cores. and the low permeability was estimated to be achieved by the partial crystallization and the resultant change in magnetization mode to the magnetization rotation mode. The fraction of crystallized part was estimated to be approximately 15 % in weight. A decrease in AC-permeability due to an application of DC-bias field was smaller than that of a Mn-Zn ferrite core with air-gap (μ=120) but larger than that of a Mo permalloy powder core (μ=130). The core loss, which is comparable with dial of a Co-based amorphous cut core (μ=200) and a Sendust powder core (μ=100), decreased with increasing the magnitude of DC-bias field at low frequencies such as 10 kHz and increased at high frequencies such as 150 kHz. This increase may be attributed to in-plane eddy current loss at high frequencies.
