MAGNETIC SENSOR

• US 20120217961A1
• Filed: 05/07/2012
• Published: 08/30/2012
• Est. Priority Date: 01/20/2010
• Status: Abandoned Application

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: ANDO, Hideto, SUGIHARA, Shinji, NOGUCHI, Takafumi
• Application Number:
  US13/465,954
• Publication Number:
  US 20120217961A1
• Time in Patent Office: Days
• US Class Current: 324/252
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A magnetic sensor includes a plurality of magnetoresistance effect elements and soft magnetic bodies. Each of the magnetoresistance effect elements is formed by stacking a magnetic layer and a non-magnetic layer on a substrate so as to exhibit a magnetoresistance effect. The magnetoresistance effect element is configured such that element portions and electrode layers are alternately disposed. A soft magnetic body is disposed on one and the other sides of each of the element portions in the Y direction, and the soft magnetic bodies are displaced from each other in the X direction. With this arrangement, an external magnetic field applied in the X1 direction is changed into an external magnetic field in the Y direction when passing through the soft magnetic bodies, and the changed external magnetic field flows into the element portions.

Claims

1. A magnetic sensor comprising:

a magnetoresistance effect element configured to be formed by stacking a magnetic layer and a non-magnetic layer on a substrate so as to exhibit a magnetoresistance effect; and

soft magnetic bodies configured to change a direction of an external magnetic field applied from a direction orthogonal to a direction of a sensitivity axis of the magnetoresistance effect element into the direction of the sensitivity axis and to supply the external magnetic field to the magnetoresistance effect element, the soft magnetic bodies being disposed so as not to be in contact with the magnetoresistance effect element, wherein;

a Y direction of the magnetoresistance effect element is the direction of the sensitivity axis, and the soft magnetic bodies are each disposed on one side and the other side of the magnetoresistance effect element in the Y direction, among the soft magnetic bodies, a first soft magnetic body included in the softmagnetic bodies disposed on the one side of the magnetoresistance effect element and a second soft magnetic body included in the softmagnetic bodies disposed on the other side of the magnetoresistance effect element being displaced from each other in an X direction, which is orthogonal to the Y direction, so that the X direction of an external magnetic field applied from the X direction is changed to the Y direction between the first and second soft magnetic bodies and the external magnetic field flows into the magnetoresistance effect element; and

the magnetoresistance effect element includes an element linked body extending in the X direction, the element linked body including a plurality of element portions disposed with a space between the element portions in the X direction and an electrode layer disposed between the element portions, a soft magnetic body being disposed on each of one side and the other side of each of the element portions so that the soft magnetic bodies disposed on the one side and the other side of each of the element portions are displaced from each other in the X direction.

2. The magnetic sensor according to claim 1, wherein the first and second soft magnetic bodies are displaced from each other in the X direction so that the first and second soft magnetic bodies do not oppose each other in the Y direction.

3. The magnetic sensor according to claim 2, wherein the first and second soft magnetic bodies each include an end portion at which the direction of the external magnetic field is changed to the direction of the sensitivity axis between the first and second soft magnetic bodies, the end portion of the first soft magnetic body including an X1 end surface facing in an X1 direction, the X1 end surface being positioned, in an X2 direction, so as to be spaced apart from an X1 side edge portion of a first side surface, the first side surface being the one side of the magnetoresistance effect element, the end portion of the second soft magnetic body including an X2 end surface facing in the X2 direction, the X2 end surface being positioned, in the X1 direction, so as to be spaced apart from an X2 side edge portion of a second side surface, the second side surface being the other side of the magnetoresistance effect element.

4. The magnetic sensor according to claim 3, wherein the X1 end surface of the first soft magnetic body is positioned on a line that extends in the Y direction from an X-direction-widthwise center of the first side surface of the magnetoresistance effect element, and the X2 end surface of the second soft magnetic body is positioned on a line that extends in the Y direction from an X-widthwise center of the second side surface of the magnetoresistance effect element.

5. The magnetic sensor according to claim 1, wherein, when one side in the X direction is taken to be a front side and the other side in the X direction is taken to be a back side, a front end portion of a soft magnetic body disposed on the one side of each of the element portions opposes the element portion in the Y direction, and a back end portion of a soft magnetic body disposed on the other side of each of the element portions opposes the element portion in the Y direction, or the back end portion of a soft magnetic body disposed on the one side of each of the element portions opposes the element portion in the Y direction, and the front end portion of a soft magnetic body disposed on the other side of each of the element portions opposes the element portion in the Y direction.

6. The magnetic sensor according to claim 5, wherein the element linked body is provided in a plurality, the plurality of element linked bodies being disposed with a space between the element linked bodies in the Y direction, the element linked bodies being formed in a meandering shape by connecting end portions of the element linked bodies to each other, and the soft magnetic bodies are disposed between the element linked bodies with a space between the soft magnetic bodies in the X direction, each of the soft magnetic bodies being used for the element linked bodies positioned adjacent to each other.

7. The magnetic sensor according to claim 4, wherein the magnetoresistance effect element includes a plurality of element portions disposed with a space between the element portions in the Y direction and hard bias layers positioned between the element portions so as to connect the element portions, and the hard bias layers are disposed alternately between X1 end portions of the element portions and X2 end portions of the element portions so that a bias magnetic field applied from the X direction flows into the element portions and so that a direction of the bias magnetic field flowing into one of the element portions connected to each other with the hard bias layer is opposite to a direction of the bias magnetic field flowing into the other one of the element portions connected to each other with the hard bias layer, and a soft magnetic body is disposed on each of one side and the other side of each of the element portions in the Y direction so that the soft magnetic bodies disposed on the one side and the other side of each of the element portions are displaced from each other in the X direction.

8. The magnetic sensor according to claim 7, wherein the X1 end portions and the X2 end portions of the element portions are obliquely tilted from extending in the Y direction so as to be tilted toward the X direction.

9. The magnetic sensor according to claim 8, wherein, when one side in the X direction is taken to be a front side and the other side in the X direction is taken to be a back side, a front end portion of a soft magnetic body disposed on the one side of each of the element portions opposes the element portion in the Y direction, and a back end portion of a soft magnetic body disposed on the other side of each of the element portions opposes the element portion in the Y direction, or the back end portion of a soft magnetic body disposed on the one side of each of the element portions opposes the element portion in the Y direction, and the front end portion of a soft magnetic body disposed on the other side of each of the element portions opposes the element portion in the Y direction.

10. The magnetic sensor according to claim 9, wherein the element linked body is provided in a plurality, the plurality of element linked bodies extending in the Y direction and being disposed with a space between the element linked bodies in the X direction, each of the plurality of element linked bodies including the element portions and the hard bias layers, the element linked bodies being formed in a meandering shape by connecting end portions of the element linked bodies to each other, and the plurality of soft magnetic bodies are disposed between the element linked bodies, each of the soft magnetic bodies being used for the element linked bodies positioned adjacent to each other.

11. The magnetic sensor according to claim 1, wherein:

the magnetoresistance effect element includes an element linked body, the element linked body including a plurality of first element portions, a plurality of second element portions, and an electrode layer connecting the first and second element portions, the plurality of first element portions being disposed with a space between the first element portions in the X direction, the plurality of second element portions being displaced from the plurality of first element portions in the X direction and being disposed with a space between the second element portions in the Y direction, which is orthogonal to the X direction;

the Y direction of the first and second element portions is the direction of the sensitivity axis, and a soft magnetic body is disposed on each of one and the other sides of each of the first and second element portions such that the soft magnetic body opposes the first or second element portion in the Y direction in a non-contact manner; and

the soft magnetic bodies disposed on the one side and the other side of each of the first and second element portions are displaced from each other in the X direction so that a direction of an external magnetic field applied from the X direction is changed to the Y direction between the soft magnetic bodies and the external magnetic field flows into each of the first and second element portions.

12. The magnetic sensor according to claim 11, wherein the element linked body is provided in a plurality, the plurality of element linked bodies being disposed with a space between the element linked bodies in the Y direction, end portions of the element linked bodies being connected to each other, and, between the element linked bodies, the soft magnetic bodies are disposed with a space between the soft magnetic bodies in the X direction, each of the soft magnetic bodies being used for the element linked bodies positioned adjacent to each other.

13. The magnetic sensor according to claim 1, wherein:

the magnetoresistance effect element is provided in a plurality, the magnetic sensor is formed by a bridge circuit including first, second, third, and fourth magnetoresistance effect elements;

the first and third magnetoresistance effect elements are connected to an input terminal, while the second and fourth magnetoresistance effect elements are connected to a ground terminal, and a first output terminal is connected between the first and second magnetoresistance effect elements, while a second output terminal is connected between the third and fourth magnetoresistance effect elements;

the first, second, third, and fourth magnetoresistance effect elements are formed by an identical film structure and pinned magnetization directions of pinned magnetic layers provided for the individual first, second, third, and fourth magnetoresistance effect elements are identical; and

an arrangement of the soft magnetic bodies with respect to the first and fourth magnetoresistance effect elements is different from an arrangement of the soft magnetic bodies with respect to the second and third magnetoresistance effect elements so that a direction of an external magnetic field flowing into the first and fourth magnetoresistance effect elements is opposite to a direction of an external magnetic field flowing into the second and third magnetoresistance effect elements.

14. The magnetic sensor according to claim 13, wherein a Y direction of each of the first, second, third, and fourth magnetoresistance effect elements is the direction of the sensitivity axis, and a soft magnetic body is disposed on each of one side and the other side of each of the first, second, third, and fourth magnetoresistance effect elements in the Y direction, and a soft magnetic body disposed on the one side of each of the first, second, third, and fourth magnetoresistance effect elements and a soft magnetic body disposed on the other side of each of the first, second, third, and fourth magnetoresistance effect elements are displaced from each other in the X direction so that the X direction of an external magnetic field applied from the X direction is changed to the Y direction between the soft magnetic bodies disposed on the one and the other sides of each of the first, second, third, and fourth magnetoresistance effect elements and the external magnetic field flows into each of the first, second, third, and fourth magnetoresistance effect element, and a direction in which the soft magnetic bodies disposed on the one side and the other side of each of the first and fourth magnetoresistance effect elements are displaced from each other with respect to the first and fourth magnetoresistance effect elements is opposite to a direction in which the soft magnetic bodies disposed on the one side and the other side of each of the second and third magnetoresistance effect elements are displaced from each other with respect to the second and third magnetoresistance effect elements.

15. The magnetic sensor according to claim 14, wherein:

each of the first, second, third, and fourth magnetoresistance effect elements includes an element linked body extending in the X direction, the element linked body including a plurality of element portions disposed with a space between the element portions in the X direction and an electrode layer disposed between the element portions; and

when one side in the X direction is taken to be a front side and the other side in the X direction is taken to be a back side, in the first and fourth magnetoresistance effect elements, a front end portion of a soft magnetic body disposed on the one side of each of the element portions forming the first and fourth magnetoresistance effect elements opposes the element portion in the Y direction, while a back end portion of a soft magnetic body disposed on the other side of each of the element portions opposes the element portion in the Y direction, and in the second and third magnetoresistance effect elements, the back end portion of a soft magnetic body disposed on the one side of each of the element portions forming the second and third magnetoresistance effect elements opposes the element portion in the Y direction, while the front end portion of a soft magnetic body disposed on the other side of each of the element portions opposes the element portion in the Y direction.