| 摘要 |
PURPOSE:To achieve a better judgement of magnetic pole with a small apparatus simple in the construction, by making a ferromagnetic magnetoresistance element MR of one element zigzag in shape while a bias magnet is used in which a magnet with the plane almost square is magnetized at a specified angle. CONSTITUTION:A bias magnetic field HB is applied to an element MR1 which uses a permalloy thin film, made so zigzag as to increase a resistance value. Magnets 4a and 4b for detecting position of a magnetic head employ a cylindrical ferrite magnet in a specified size and the MR1 is connected to a DC power source 3 through a resistance 2. here, the MR1 is fastened to the bias magnet (not illustrated) and the direction in which the bias magnet is magnetized is decided to match the direction of the MR1 thereby enabling accurate detection of position. Then, when a bias magnetic field is applied at 45 deg. to the direction of current flowing through the MR1, the center of variation of magnetoresistance is at a bias point free from variations to obtain the same detection voltage regardless of the polarity, positive or negative, of the magnetic field.
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