Magnetic sensor, production process of the magnetic sensor and magnetic array suitable for the production process
First Claim
1. A magnet array including plural permanent magnets, each having an approximately rectangular parallelepiped shape and having a sectional shape, perpendicular to one central axis of the rectangular parallelepiped, which is approximately square, and each having poles formed at both edge faces, one of which has the approximately square shape perpendicular to the central axis of the rectangular parallelepiped;
- wherein the plural permanent magnets are arranged in such a manner that each center of gravity of the edge faces having the approximately square shape is matched with a lattice point of a tetragonal lattice, a certain side of sides forming one of the edge faces of the plural permanent magnets disposed in a certain row of the tetragonal lattice and a certain side of sides forming one of the edge faces of the other plural permanent magnets disposed in the same row of the tetragonal lattice is in a same straight line, all the edge faces having the square shapes of the permanent magnets are placed in an approximately same single plane, and any two of the polarities of the magnetic poles of the permanent magnets disposed adjacent each other and spaced by the shortest route are different each other.
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Abstract
The present invention aims to provide a magnetic sensor provided with a magnetoresistive effect element capable of stably maintaining a direction of magnetization in a magnetic domain of a free layer.
The magnetic sensor includes a magnetoresistive effect element provided with narrow zonal portions 11a . . . 11a including a pinned layer and a free layer. Disposed below both ends of the free layer are bias magnet films 11b . . . 11b composed of a permanent magnet that applies to the free layer a bias magnetic field in a predetermined direction and an initializing coil 31 that is disposed in the vicinity of the free layer and applies to the free layer a magnetic field having the direction same as that of the bias magnetic field by being energized under a predetermined condition. Further, magnetizing the bias magnet films and fixing the direction of magnetization of the pinned layer are performed by a magnetic field formed by a magnet array configured such that plural permanent magnets are arranged on a lattice point of a tetragonal lattice and a polarity of a magnet pole of each permanent magnet is different from a polarity of the other adjacent magnet pole spaced by the shortest route.
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Citations
7 Claims
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1. A magnet array including plural permanent magnets, each having an approximately rectangular parallelepiped shape and having a sectional shape, perpendicular to one central axis of the rectangular parallelepiped, which is approximately square, and each having poles formed at both edge faces, one of which has the approximately square shape perpendicular to the central axis of the rectangular parallelepiped;
- wherein
the plural permanent magnets are arranged in such a manner that each center of gravity of the edge faces having the approximately square shape is matched with a lattice point of a tetragonal lattice, a certain side of sides forming one of the edge faces of the plural permanent magnets disposed in a certain row of the tetragonal lattice and a certain side of sides forming one of the edge faces of the other plural permanent magnets disposed in the same row of the tetragonal lattice is in a same straight line, all the edge faces having the square shapes of the permanent magnets are placed in an approximately same single plane, and any two of the polarities of the magnetic poles of the permanent magnets disposed adjacent each other and spaced by the shortest route are different each other.
- wherein
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2. A magnet array including plural permanent magnets, each having an approximately rectangular parallelepiped shape and having a sectional shape, perpendicular to one central axis of the rectangular parallelepiped, which is approximately square, and each having poles formed at both edge faces, one of which has the approximately square shape perpendicular to the central axis of the rectangular parallelepiped and a thin plate-like yoke formed of a magnetic material;
- wherein
the plural permanent magnets are arranged in such a manner that each center of gravity of the edge faces having the approximately square shape is matched with a lattice point of a tetragonal lattice, a certain side of sides forming one of the edge faces of the plural permanent magnets disposed in a certain row of the tetragonal lattice and a certain side of sides forming one of the edge faces of the other plural permanent magnets disposed in the same row of the tetragonal lattice is in a same straight line, all the edge faces having the square shapes of the permanent magnets are placed in an approximately same single plane, and any two of the polarities of the magnetic poles of the permanent magnets disposed adjacent each other and spaced by the shortest route are different each other; and
the yoke comprises plural through holes each of which has a shape which is the approximately same as the sectional shape which is approximately square and the holes being arranged at the positions where the permanent magnets are disposed, and the yoke being arranged in such a manner that the same single plane in which all the edge faces of the permanent magnets are placed is disposed between an upper surface and a lower surface of the yoke when the permanent magnets are inserted into the through holes. - View Dependent Claims (3, 4, 5, 6)
- wherein
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7. A magnet array including plural permanent magnets, each having an approximately rectangular parallelepiped shape and having a sectional shape, perpendicular to one central axis of the rectangular parallelepiped, which is approximately square, and each having poles formed at both edge faces, one of which has the approximately square shape perpendicular to the central axis of the rectangular parallelepiped and a thin plate-like yoke formed of a magnetic material;
- wherein
the plural permanent magnets are arranged in such a manner that each center of gravity of the edge faces having the approximately square shape is matched with a lattice point of a tetragonal lattice, a certain side of sides forming one of the edge faces of the plural permanent magnets disposed in a certain row of the tetragonal lattice and a certain side of sides forming one of the edge faces of the other plural permanent magnets disposed in the same row of the tetragonal lattice is in a same straight line, all the edge faces having the square shapes of the permanent magnets are placed in an approximately same single plane, and any two of the polarities of the magnetic poles of the permanent magnets disposed adjacent each other and spaced by the shortest route are different each other; and
the yoke comprises plural through holes each of which has a shape which is the approximately same as the sectional shape which is approximately square and the holes being arranged at the positions where the permanent magnets are disposed, and the yoke being arranged in such a manner that the same single plane in which all the edge faces of the permanent magnets are placed is disposed between an upper surface and a lower surface of the yoke when the permanent magnets are inserted into the through holes;
whereinthe yoke has through openings serving as air gaps formed between the through holes that are adjacent each other and that are spaced by a shortest route;
whereinthe yoke has openings at regions each of which is surrounding a center of gravity of a square drawn by lines connecting the lattice points of the tetragonal lattice in a plan view;
whereineach of the through holes of the yoke has a square portion having a square shape which is the approximately same as the shape of the sectional square shape of the permanent magnet in a plan view and a margin portions swelling outwardly from the square at each of corners of the square portion.
- wherein
Specification