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In this study, we investigate the output properties of the orthogonal fluxgate sensor fabricated with a cylinder-shaped ferrite core, and examine whether it could show both high sensitivity and wide measurement range for the application of magnetic treatment facility for surface vessels and submarines. The excitation coil and pickup coil are 10 turns and 280 turns respectively. To gain the wide measurement range over 30 Oe, we design the shape of magnetic core through FEM analysis. It is found that a stable fundamental mode operation would be possible when an adequate DC bias is adding to alternating excitation current. There is a resonant peak in the operation frequency dependence of output voltage, which is caused by LC resonance of pickup coil and coaxial cable. The maximum sensitivity was \sim2 V/Oe at 870 kHz, and the output increased almost linearly by external magnetic field to reach \sim30 Oe. [ABSTRACT FROM AUTHOR]

Calculated demagnetization curves agree well with the initial remnant magnetization curve. A simple analytical expression was obtained from the curve by fitting the measured initial remnant magnetization data. Anhysteretic demagnetization was performed by applying an alternating step-ramped magnetic field sequence and the vertical dc bias field, simultaneously. The influence of the vertical bias magnetic field on anhysteretic demagnetization was prominent when the amplitude of the alternating magnetic pulse was large enough to saturate the magnetization of the object. The magnetic field due to the vertical remnant magnetization could be estimated by Langevin function with parameters of \xi and HMSrem. [ABSTRACT FROM AUTHOR]