Magnetic detection device having a magnet including a stepped portion for eliminating turbulence at the MR sensor

摘要

A magnetic detection device including a biasing magnet for generating a bias magnetic field directed to an object of detection having a magnetic material; a magnetoresistance effective element disposed at an inclination of about 45° to the direction of the bias magnetic field to provide a change in resistance caused by the bias magnetic field in accordance with movement of the object of detection, so as to detect a change in state of the bias magnetic field via the change in resistance of the magnetoresistance effective element; and the biasing magnet having a hollow portion containing a holder for holding the magnetoresistance effective element in a position between a surface of the biasing magnet and the object of detection and close to the surface of the biasing element.