Giant magnetoresistance current sensor

Abstract

The invention provides a giant magnetoresistance current sensor. The giant magnetoresistance current sensor comprises a current-carrying conductor; the giant magnetoresistance sensor is located on one side of the current-carrying conductor, a nanorod of the giant magnetoresistance sensor is designed to be circular so that a free layer can form a vortex state, magnetic hysteresis is small, current detection repeatability is good, and precision is high.

Description

[Technical field]

[0001] The invention relates to a current sensor, in particular to a giant magnetoresistance current sensor. [Background technology]

[0002] Traditionally, the nanopillars of giant magnetoresistance sensors are designed in the shape of long strips, using the shape anisotropy of the free layer or the antiferromagnetic pinned free layer to detect the magnetic field or current. The disadvantage is that the hysteresis is large, resulting in poor repeatability and accuracy in the detection of the magnetic field or current.

[0003] Therefore, it is necessary to propose a solution to solve the above problems. [Summary of the invention]

[0004] One of the purposes of the present invention is to provide a giant magnetoresistance current sensor, which has good repeatability and high precision in current detection.

[0005] To solve the above problems, the present invention proposes a giant magnetoresistance current sensor, which includes: a current-carrying conductor; and a giant magnetoresistance sensor located on one side of the current-carrying conductor, wherein the nanocolumns of the giant magnetoresistance sensor are circularly designed so that the free layer forms a vortex state.

[0006] Furthermore, the current-carrying conductor includes a first leg, a second leg, and a connecting portion connecting the first leg and the second leg; the giant magnetoresistance sensor includes a first magnetically sensitive area and a second magnetically sensitive area, the first magnetically sensitive area is located on one side of the first leg, and the second magnetically sensitive area is located on one side of the second leg.

[0007] Further, the first magnetically sensitive region includes a first giant magnetoresistance sensor unit and a second giant magnetoresistance sensor unit, the second magnetically sensitive region includes a third giant magnetoresistance sensor unit and a fourth giant magnetoresistance sensor unit, the first giant magnetoresistance sensor unit, the second giant magnetoresistance sensor unit, the third giant magnetoresistance sensor unit and the fourth giant magnetoresistance sensor unit are interconnected to form a Wheatstone bridge, and the Wheatstone bridge only senses the magnetic field generated by the current flowing in the current-carrying conductor.

[0008] Furthermore, each giant magnetoresistance sensor unit includes a plurality of circular nanorods and a plurality of connecting conductors.

[0009] Furthermore, the extension direction of each giant magnetoresistance sensor unit is parallel to the leg of the current-carrying conductor, and a plurality of circular nanocolumns and a plurality of connecting conductors are arranged alternately.

[0010] Furthermore, each circular nanocolumn includes, from bottom to top, a buffer layer, an antiferromagnetic layer, a ferromagnetic layer, an interlayer, a ferromagnetic reference layer, a spacer layer, a free interlayer, a free layer and a capping layer.

[0011] Compared with the prior art, the giant magnetoresistance current sensor of the present invention adopts a circular nanocolumn design, so that the free layer forms a vortex state, the hysteresis is small, the current detection repeatability is good, and the accuracy is high.

Brief Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0013] Figure 1 The present invention is a schematic structural diagram of a giant magnetoresistance current sensor.

[0014] Figure 2 The present invention relates to Figure 1 Schematic diagram of the cross-sectional structure of the giant magnetoresistance current sensor along AA.

[0015] Figure 3 The present invention provides a curve showing the dependence of the current range and sensitivity of the giant magnetoresistance current sensor on the thickness of the free layer NiFe. [Specific implementation method]

[0016] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "front", "back", "left", "right", "vertical", "perpendicular", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0018] Figure 1 The present invention is a schematic structural diagram of a giant magnetoresistance current sensor. Figure 2 The present invention relates to Figure 1 Schematic diagram of the cross-sectional structure of the giant magnetoresistance current sensor along AA. Figure 1 and Figure 2As shown, the giant magnetoresistance current sensor 100 includes a current-carrying conductor 102 and a giant magnetoresistance sensor 101 located above the current-carrying conductor 102. The current-carrying conductor 102 includes a first leg 102a, a second leg 102b, and a connecting portion 102c connecting the first leg 102a and the second leg 102b. The first leg 102a and the second leg 102b are parallel, and the current direction in the first leg 102a is opposite to the current direction in the second leg 102b. The giant magnetoresistance sensor 101 includes a first magnetic sensitive area 101a and a second magnetic sensitive area 101b. The first magnetic sensitive area 101a is located above the first leg 102a, and the second magnetic sensitive area 101b is located above the second leg 102b. The current-carrying conductor 102 can also be called a U-shaped current-carrying conductor 102, and the U-shape in the current-carrying conductor 102 should be understood in a broad sense.

[0019] Of course, depending on the placement Figure 2 The orientation of the giant magnetoresistance current sensor 100 in the diagram can also be considered that the giant magnetoresistance sensor 101 is located below, to the left or to the right of the U-shaped current-carrying conductor 102, the first magnetic sensitive area 101a is located below, to the left or to the right of the first leg 102a, and the second magnetic sensitive area 101b is located below, to the left or to the right of the second leg 102b. Therefore, in order to avoid confusion, it can be considered that the giant magnetoresistance sensor 101 is located on one side of the U-shaped current-carrying conductor 102, the first magnetic sensitive area 101a is located on one side of the first leg 102a, and the second magnetic sensitive area 101b is located on one side of the second leg 102b. The giant magnetoresistance sensor 101 and the current-carrying conductor 102 are spaced apart from each other, which means that the giant magnetoresistance sensor 101 and the current-carrying conductor 102 are not in contact, and the giant magnetoresistance sensor 101 and the current-carrying conductor 102 are spaced apart from each other by a predetermined distance or a certain distance.

[0020] The first magnetic sensitive region 101a includes a first giant magnetoresistance sensor unit 1011a and a second giant magnetoresistance sensor unit 1012a, and the second magnetic sensitive region 101b includes a third giant magnetoresistance sensor unit 1011b and a fourth giant magnetoresistance sensor unit 1012b. The first giant magnetoresistance sensor unit 1011a, the second giant magnetoresistance sensor unit 1012a, the third giant magnetoresistance sensor unit 1011b and the fourth giant magnetoresistance sensor unit 1012b are interconnected to form a Wheatstone bridge. The magnetic field generated by the current I flowing through the current-carrying conductor 102 in the first magnetic sensitive region 101a is H1, and the magnetic field generated by the current-carrying conductor 102 in the second magnetic sensitive region 101b is -H1, and the external common mode magnetic field is H0 in the first magnetic sensitive region 101a and the second magnetic sensitive region 101b. The Wheatstone bridge only senses the magnetic field [(H1+H0)-(-H1+H0)] / 2=H1 generated by the current I flowing through the current-carrying conductor 102, and does not respond to the external common-mode magnetic field H0 at all.

[0021] Each giant magnetoresistance sensor unit includes a plurality of circular nanorods 103 and a plurality of connecting conductors 104. The extension direction of each giant magnetoresistance sensor unit is parallel to the leg of the current-carrying conductor 102. The plurality of circular nanorods 103 and the plurality of connecting conductors 104 are arranged alternately.

[0022] The circular nanocolumn 103 includes, from bottom to top, a buffer layer 1031 (preferably Ta, Ru or TaN), an antiferromagnetic layer 1032 (preferably IrMn, PtMn or FeMn), a ferromagnetic layer 1033 (preferably CoFe), an interlayer 1034 (preferably Ru), a ferromagnetic reference layer 1035 (preferably CoFe), a spacer layer 1036 (preferably Cu), a free interlayer 1037 (preferably CoFe, with a thickness of 1nm-3nm), a free layer 1038 (preferably NiFe, with a thickness of 50nm-200nm), and a capping layer 1039 (preferably Ta, Ru or TaN). The radius of the circular nanocolumn 103 can be 0.25um-5um, and the free layer 1038 forms a vortex state with small hysteresis, good repeatability and high precision in current detection. The ferromagnetic layer 1033 forms an antiferromagnetic coupling with the ferromagnetic reference layer 1035 through the interlayer 1034 (as shown by the arrow in the figure).

[0023] Specifically, the first connection end of the first giant magnetoresistance sensor unit 1011a and the first connection end of the third giant magnetoresistance sensor unit 1011b are connected to the power supply terminal VDD, the first connection end of the second giant magnetoresistance sensor unit 1012a and the first connection end of the fourth giant magnetoresistance sensor unit 1012b are connected to the ground terminal GND, the second connection end of the first giant magnetoresistance sensor unit 1011a and the second connection end of the fourth giant magnetoresistance sensor unit 1012b are connected to the first voltage output terminal Vout1, the second connection end of the second magnetoresistance sensor unit 1012a and the second connection end of the third magnetoresistance sensor unit 1011b are connected to the second voltage output terminal Vout2, the first connection end of each giant magnetoresistance sensor unit is located on the same side, and the second connection end of each giant magnetoresistance sensor unit is located on the same side. The working principle of each giant magnetoresistance sensor unit and the Wheatstone bridge can refer to the prior art, which is not the focus of the present invention and will not be repeated.

[0024] See also Figure 3 As shown, the dependence curve 300 of the current range and sensitivity of the giant magnetoresistance current sensor of the present invention on the thickness of the free layer NiFe is shown: wherein the coupling strength of the current flowing through the U-shaped current-carrying conductor 102 in the magnetic sensitive area is 1.5G / A, and the radius of the circular nanocolumn 103 is 1um. It can be seen that the current range increases linearly with the increase of the thickness of the free layer NiFe, and the sensitivity decreases with the increase of the thickness of the free layer NiFe.

[0025] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0026] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify and vary the above embodiments within the scope of the present invention.

Claims

1. A giant magnetoresistance current sensor, characterized in that: It includes: Current-carrying conductor; and A giant magnetoresistance sensor is located on one side of the current-carrying conductor, wherein the nanocolumns of the giant magnetoresistance sensor are circularly designed so that the free layer forms a vortex state.

2. The giant magnetoresistance current sensor according to claim 1, characterized in that: The current-carrying conductor comprises a first leg, a second leg and a connecting portion connecting the first leg and the second leg; The giant magnetoresistance sensor comprises a first magnetic sensitive region and a second magnetic sensitive region, wherein the first magnetic sensitive region is located at one side of the first leg portion, and the second magnetic sensitive region is located at one side of the second leg portion.

3. The giant magnetoresistance current sensor according to claim 2, characterized in that: The first magnetic sensitive area includes a first giant magnetoresistance sensor unit and a second giant magnetoresistance sensor unit, the second magnetic sensitive area includes a third giant magnetoresistance sensor unit and a fourth giant magnetoresistance sensor unit, the first giant magnetoresistance sensor unit, the second giant magnetoresistance sensor unit, the third giant magnetoresistance sensor unit and the fourth giant magnetoresistance sensor unit are interconnected to form a Wheatstone bridge, and the Wheatstone bridge only senses the magnetic field generated by the current flowing in the current-carrying conductor.

4. The giant magnetoresistance current sensor according to claim 3, characterized in that: Each giant magnetoresistive sensor unit includes a number of circular nanorods and a number of connecting conductors.

5. The giant magnetoresistance current sensor according to claim 4, characterized in that: The extension direction of each giant magnetoresistance sensor unit is parallel to the leg of the current-carrying conductor, and a plurality of circular nanocolumns and a plurality of connecting conductors are arranged alternately.

6. The giant magnetoresistance current sensor according to claim 4, characterized in that: Each circular nanocolumn includes, from bottom to top, a buffer layer, an antiferromagnetic layer, a ferromagnetic layer, an interlayer, a ferromagnetic reference layer, a spacer layer, a free interlayer, a free layer and a capping layer.

7. The giant magnetoresistance current sensor according to claim 6, characterized in that: The radius of the circular nanocolumn is 0.25um-5um, and the free layer forms a vortex state with small hysteresis.

8. The giant magnetoresistance current sensor according to claim 6, characterized in that: The ferromagnetic layer forms an antiferromagnetic coupling with the ferromagnetic reference layer through the interlayer.

9. The giant magnetoresistance current sensor according to claim 6, characterized in that: The buffer layer is Ta, Ru or TaN, the antiferromagnetic layer is IrMn, PtMn or FeMn, the ferromagnetic layer is CoFe, the interlayer is Ru, the ferromagnetic reference layer is CoFe, the spacer layer is Cu, the free interlayer is CoFe, the thickness of the free interlayer is 1nm-3nm, the free layer is NiFe, and the covering layer is Ta, Ru or TaN.

10. The giant magnetoresistance current sensor according to claim 6, characterized in that: The thickness of the free layer is 50nm-200nm.

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