軟磁性用ディジタル化M-Hループトレーサー

概要

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Analysis of the measuring sensitivity of a conventional M-H loop tracer revealed that the sensitivity is limited by undesirable signals, caused by imbalance of a pick-up coil pair, use of a non-ideal electronic integrator, and/or the presence of ambient magnetic or conductive bodies. Most of these noises are periodic and synchronized with the exciting magnetic field at 50-60 Hz. This paper proposes a new scheme utilizing digital signal-processing technique and virtual instrument software, to reduce such noises effectively, taking account of the above-mentioned noise properties. In the scheme, a pick-up coil signal without a magnetic thin film is first sampled and stored in memory as a background noise, then another signal with the thin film is sampled and the stored background noise is reduced. A pick-up coil pair, linear amplifiers, and digital-signal-processing software were optimally designed and installed. A newly designed M-H loop tracer can measure thin soft-magnetic films with a magnetic moment as small as 2.5×10^-1 emu.
社団法人日本磁気学会の論文
1998-07-01