Magnetic sensor

Patent metadata

Field	Value
Publication number	US-9823315-B2
Application number	US-201314410654-A
Country	US
Kind code	B2
Filing date	Jul 3, 2013
Priority date	Jul 5, 2012
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

In a magnetic sensor, a pinned layer covers a wiring layer on a side opposite to a substrate with respect to the wiring layer and includes a bent portion having a bent shape in cross section. Free layers are arranged on a side opposite to the substrate with respect to the pinned layer. The size of the free layers in a planar direction is set to a size smaller than the size of the pinned layer in the planar direction. A magnetic field leaking from the pinned layer may form a closed loop adjacent to the substrate, that is, on a side opposite to the free layers with respect to the substrate. Therefore, influence of the magnetic field leaking from the pinned layer on the free layers can be restricted.

First claim

The invention claimed is:

1. A magnetic sensor comprising:
a magnetization fixed layer disposed adjacent to a surface of a substrate and having a magnetization direction that is fixed in a direction parallel to a planar direction of the substrate;
a ferromagnetic layer disposed on a side opposite to the substrate with respect to the magnetization fixed layer, and having a magnetization direction that changes according to an external magnetic field; and
a non-magnetic intermediate layer interposed between the magnetization fixed layer and the ferromagnetic layer, and having a resistance value that changes according to an angle between the magnetization direction of the magnetization fixed layer and the magnetization direction of the ferromagnetic layer, wherein
an application angle of the external magnetic field is measured based on a resistance value between the magnetization fixed layer and the ferromagnetic layer,
the magnetization fixed layer includes a bent portion having a bent shape in cross section in which a first end portion and a second end portion of a flat portion, which defines a planar direction parallel to the planar direction of the substrate, are respectively bent toward the substrate, and
a magnetic field leaking from the magnetization fixed layer forms a closed loop excluding the ferromagnetic layer to suppress interaction between the ferromagnetic layer and the magnetic field leaking from the magnetization fixed layer.

2. A magnetic sensor comprising:
a magnetization fixed layer disposed adjacent to a surface of a substrate and having a magnetization direction fixed in a direction parallel to a planar direction of the substrate;
a ferromagnetic layer disposed on a side opposite to the substrate with respect to the magnetization fixed layer, and having a magnetization direction that changes according to an external magnetic field; and
a non-magnetic intermediate layer interposed between the magnetization fixed layer and the ferromagnetic layer, and having a resistance value that changes according to an angle between the magnetization direction of the magnetization fixed layer and the magnetization direction of the ferromagnetic layer, wherein
an application angle of the external magnetic field is measured based on a resistance value between the magnetization fixed layer and the ferromagnetic layer,
the magnetization fixed layer includes a bent portion having a bent shape in cross section which projects toward a side opposite to the substrate, and
a magnetic field leaking from the magnetization fixed layer forms a closed loop excluding the ferromagnetic layer to suppress interaction between the ferromagnetic layer and the magnetic field leaking from the magnetization fixed layer.

3. The magnetic sensor according to claim 1 , wherein a size of the ferromagnetic layer in the planar direction is set to a same size as a size of the magnetization fixed layer in the planar direction, or to a size smaller than the size of the magnetization fixed layer in the planar direction.

4. The magnetic sensor according to claim 1 , wherein
the magnetization fixed layer includes:
a laminated ferrimagnetic structure including a first magnetic layer and a second magnetic layer and a non-magnetic layer interposed between the first magnetic layer and the second magnetic layer; and
an antiferromagnetic layer arranged between the substrate and the laminated ferrimagnetic structure.

5. The magnetic sensor according to claim 1 , wherein the magnetization fixed layer is made of a material having a coercive force higher than that of the ferromagnetic layer.

6. The magnetic sensor according to claim 1 , wherein
a projection portion is disposed on the surface of the substrate, the projection portion having a projected shape in cross section projecting in a plate thickness direction of the substrate, and
the bent portion of the magnetization fixed layer is disposed along the projection portion.

7. The magnetic sensor according to claim 6 , wherein
the projection portion includes a first projection layer and a second projection layer, the first projection layer having a projected shape in cross section projecting from the substrate in a direction orthogonal to the planar direction of the substrate, the second projection layer covering the first projection layer on a side opposite to the substrate.

8. The magnetic sensor according to claim 7 , wherein the first projection layer is made of an electric insulating material.

9. The magnetic sensor according to claim 7 , wherein the second projection layer is made of an electric insulating material.

10. The magnetic sensor according to claim 7 , wherein the first projection layer is made of a conductive material.

11. The magnetic sensor according to claim 7 , wherein the second projection layer is made of a conductive material.

12. The magnetic sensor according to claim 7 , wherein the first projection layer is formed by removing an extra portion other than the first projection layer in a first film molded along the surface of the substrate through etching.

13. The magnetic sensor according to claim 12 , wherein the second projection layer is formed by removing an extra portion other than the second projection layer in a second film molded to cover both of the substrate and the first film through etching.

14. The magnetic sensor according to claim 1 , wherein a high permeability member that is made of a material having a permeability higher than that of the substrate is disposed between the substrate and the magnetization fixed layer to form a magnetic field path through which a magnetic field leaking from the magnetization fixed layer passes.

15. The magnetic sensor according to claim 1 , wherein the magnetization fixed layer, the ferromagnetic layer, and the non-magnetic intermediate layer constitute a Tunneling Magneto Resistance element.

16. The magnetic sensor according to claim 1 , wherein the magnetization fixed layer, the ferromagnetic layer, and the non-magnetic intermediate layer constitute a Giant Magneto Resistance element.

17. The magnetic sensor according to claim 2 , wherein
a projection portion is disposed on the surface of the substrate, the projection portion having a projected shape in cross section projecting in a plate thickness direction of the substrate, and
the bent portion of the magnetization fixed layer is disposed along the projection portion.

18. The magnetic sensor according to claim 1 , wherein
the magnetic field leaking from the magnetization fixed layer extends from the magnetization fixed layer and into the substrate without extending through the ferromagnetic layer.

19. The magnetic sensor according to claim 2 , wherein
the magnetic field leaking from the magnetization fixed layer extends from the magnetization fixed layer and into the substrate without extending through the ferromagnetic layer.

Assignees

• Denso Corp

Inventors

• Yano Toshifumi
• Furuichi Takamoto

Classifications

• G01R33/09 Primary

  Magnetoresistive devices · CPC title

• G01R33/098 Primary

  comprising tunnel junctions, e.g. tunnel magnetoresistance sensors · CPC title

• G01R33/093

  using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00) · CPC title

• H01L43/08

  Electricity · mapped topic

• H01F10/3254

  the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ] · CPC title