Magnetic sensor

Patent metadata

Field	Value
Publication number	US-9664768-B2
Application number	US-201314390413-A
Country	US
Kind code	B2
Filing date	Apr 17, 2013
Priority date	Apr 23, 2012
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A TMR element and a corrective AMR element are series-connected between a power supply and a ground. The resistance value of the corrective AMR element is set so as to offset an output error in the rotation angle of an external magnetic field, which is included in the resistance value of the TMR element. The resistance value of the corrective AMR element is smaller than that of the TMR element. An increased voltage can be applied from the power supply to the TMR element. It is possible to increase, in the resistance value of the TMR element, the amount of change that depends on the rotation angle of the external magnetic field. This makes it possible to increase, in the output of a magnetic sensor, the amount of change that depends on the rotation angle of the external magnetic field. The sensitivity of the magnetic sensor can be increased.

First claim

The invention claimed is:

1. A magnetic sensor comprising:
a magnetoresistive element including
a magnetization fixing layer whose magnetization direction is fixed with respect to an external magnetic field,
a ferromagnetic layer whose magnetization direction rotates in accordance with the external magnetic field, and
a non-magnetic interlayer that is sandwiched between the magnetization fixing layer and the ferromagnetic layer, the non-magnetic interlay having a resistance value that varies in accordance with an angle between the magnetization direction of the magnetization fixing layer and the magnetization direction of the ferromagnetic layer; and

an anisotropic magnetoresistive element having a resistance value that is smaller than a resistance value of the magnetoresistive element and varies with a rotation angle of the external magnetic field,
wherein the external magnetic field is measured in accordance with a combined resistance value obtained by combining the resistance value of the magnetoresistive element and the resistance value of the anisotropic magnetoresistive element, and
wherein the resistance value of the anisotropic magnetoresistive element is set to offset an output error in the rotation angle, the output error being included in the resistance value of the magnetoresistive element.

2. The magnetic sensor according to claim 1 , wherein the angle between the direction of easy axis of magnetization of the anisotropic magnetoresistive element and the magnetization direction of the magnetization fixing layer is set so that the resistance value of the anisotropic magnetoresistive element offsets the output error in the rotation angle, the output error being included in the resistance value of the magnetoresistive element.

3. The magnetic sensor according to claim 1 , wherein the magnetoresistive element and the anisotropic magnetoresistive element are series-connected between a power supply and a ground.

4. The magnetic sensor according to claim 1 , wherein the magnetoresistive element and the anisotropic magnetoresistive element are parallel-connected between a power supply and a ground.

5. The magnetic sensor according to claim 1 , wherein the magnetoresistive element and the anisotropic magnetoresistive element measure the rotation angle of the external magnetic field.

6. The magnetic sensor according to claim 1 , wherein the magnetoresistive element and the anisotropic magnetoresistive element measure an intensity of the external magnetic field.

7. The magnetic sensor according to claim 1 , wherein the anisotropic magnetoresistive element includes one of a metal and a metal alloy, the metal including one metal of Ni, Fe, and Co, the metal alloy including at least two metals of Ni, Fe, and Co.

8. The magnetic sensor according to claim 1 , wherein the magnetoresistive element and the anisotropic magnetoresistive element are formed in an identical plane.

9. The magnetic sensor according to claim 1 , wherein the magnetoresistive element and the anisotropic magnetoresistive element are formed in different planes.

10. The magnetic sensor according to claim 1 , wherein a plurality of the magnetoresistive elements are disposed.

11. The magnetic sensor according to claim 10 , wherein the plurality of the magnetoresistive elements form a bridge circuit.

12. The magnetic sensor according to claim 11 , wherein a plurality of the anisotropic magnetoresistive elements are disposed.

13. The magnetic sensor according to claim 12 , wherein the plurality of the anisotropic magnetoresistive elements form a bridge circuit.

14. The magnetic sensor according to claim 1 , wherein at least two anisotropic magnetoresistive elements are disposed; and wherein the magnetoresistive element is disposed between the two anisotropic magnetoresistive elements.

15. The magnetic sensor according to claim 1 , wherein the magnetoresistive element is a TMR (Tunnel Magnet-Resisitive) element.

16. The magnetic sensor according to claim 1 , wherein the magnetoresistive element is a GMR (Giant Magneto-Resistive) element.

17. A magnetic sensor comprising:
a magnetoresistive element including
a magnetization fixing layer whose magnetization direction is fixed with respect to an external magnetic field,
a ferromagnetic layer whose magnetization direction rotates in accordance with the external magnetic field, and
a non-magnetic interlayer that is sandwiched between the magnetization fixing layer and the ferromagnetic layer, the non-magnetic interlay having a resistance value that varies in accordance with an angle between the magnetization direction of the magnetization fixing layer and the magnetization direction of the ferromagnetic layer; and

an anisotropic magnetoresistive element having a resistance value that is smaller than a resistance value of the magnetoresistive element and varies with a rotation angle of the external magnetic field,
wherein the external magnetic field is measured in accordance with a combined resistance value obtained by combining the resistance value of the magnetoresistive element and the resistance value of the anisotropic magnetoresistive element, and
wherein at least two anisotropic magnetoresistive elements are disposed; and wherein the magnetoresistive element is disposed between the two anisotropic magnetoresistive elements.

18. The magnetic sensor according to claim 17 , wherein the magnetoresistive element and the anisotropic magnetoresistive element are series-connected between a power supply and a ground.

19. The magnetic sensor according to claim 17 , wherein the magnetoresistive element and the anisotropic magnetoresistive element are parallel-connected between a power supply and a ground.

20. The magnetic sensor according to claim 17 , wherein the magnetoresistive element and the anisotropic magnetoresistive element measure the rotation angle of the external magnetic field.

21. The magnetic sensor according to claim 17 , wherein the magnetoresistive element and the anisotropic magnetoresistive element measure an intensity of the external magnetic field.

22. The magnetic sensor according to claim 17 , wherein the anisotropic magnetoresistive element includes one of a metal and a metal alloy, the metal including one metal of Ni, Fe, and Co, the metal alloy including at least two metals of Ni, Fe, and Co.

23. The magnetic sensor according to claim 17 , wherein the magnetoresistive element and the anisotropic magnetoresistive element are formed in an identical plane.

24. The magnetic sensor according to claim 17 , wherein the magnetoresistive element and the anisotropic magnetoresistive element are formed in different planes.

25. The magnetic sensor according to claim 17 , wherein a plurality of the magnetoresistive elements are disposed.

26. The magnetic sensor according to claim 25 , wherein the plurality of the magnetoresistive elements form a bridge circuit.

27. The magnetic sensor according to claim 26 , wherein a plurality of the anisotropic magnetoresistive elements are disposed.

28. The magnetic sensor according to claim 27 , wherein the plurality of the anisotropic magnetoresistive elements form a bridge circuit.

29. The magnetic sensor according to claim 17 , wherein the magnetoresistive element is a TMR (Tunnel Magnet-Resisitive) element.

30. The magnetic sensor according to claim 17

Assignees

• Denso Corp

Inventors

• Furuichi Takamoto
• Yano Toshifumi
• Yokura Hisanori

Classifications

• G01R33/098

  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

• G01R35/00 Primary

  Testing or calibrating of apparatus covered by the other groups of this subclass · CPC title

• B82Y25/00

  Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance · CPC title

• G01R33/096 Primary

  anisotropic magnetoresistance sensors · CPC title