CN102841324A

CN102841324A - Circuit structure for anisotropic magnetic resistance device

Info

Publication number: CN102841324A
Application number: CN2012103247187A
Authority: CN
Inventors: 吴俊�; 张卫; 王鹏飞; 孙清清; 周鹏
Original assignee: Fudan University
Current assignee: Fudan University
Priority date: 2012-09-05
Filing date: 2012-09-05
Publication date: 2012-12-26

Abstract

The invention belongs to the technical field of magnetic field detection, and in particular relates to a circuit structure of an anisotropic magnetoresistance device. The present invention uses a specific circuit structure to manufacture anisotropic magnetoresistive devices, so that the overall volume of the anisotropic magnetoresistive device is reduced and the measured magnetic field is concentrated in a smaller area, so that the anisotropic magnetoresistive device can It can be more flexibly used in other devices to achieve the purpose of device miniaturization and intensification.

Description

A kind of circuit structure of anisotropic magnetoresistive device

Technical field

The invention belongs to the detection of magnetic field technical field, be specifically related to a kind of circuit structure of anisotropic magnetoresistive device.

Background technology

Anisotropic magnetoresistive (Anisotropy of magnetoresistance, AMR) found in feeromagnetic metal Fe, Ni in 1857 by W.Thomson by effect.The resistance sizes of anisotropic magnetoresistive device depends on the DOM of ferromagnetic material and the angle theta of the direction of current that passes through material; Changes in resistance roughly is the square value that is proportional to the cosine value of angle theta; The DOM of the ferromagnetic material when initial state is set is 45 degree with the angle of direction of current through material, and the DOM perpendicular to ferromagnetic material adds external magnetic field then, and the DOM of ferromagnetic material will change so; Its angle with direction of current through material also can change; We establish the ferromagnetic material DOM, and to depart from 45 jiaos angle be φ, and the resistance variations of material is into reasonable linear relationship with deviation angle φ, under the less situation of outside magnetic field; Deviation angle φ is again the ratio of the external magnetic field and the original magnetization of ferromagnetic material, so the size of external magnetic field and resistance variations are linear.

For make the anisotropic magnetoresistive device can space exploration in less magnetic field; We need with entire device be made into DOM when the initial state and the direction of current angle be fixed on 45 degree; This will use particular structural; A kind of is the structure that is called " tonsorial signboard " (Barber pole) pattern, and another kind is to be called " herringbone " (Herringbone) structure of pattern.But; Barber pole structure and Herringbone structure all are to survey the magnetic field value of certain single direction with the wheatstone bridge circuits structure; Measure the magnetic field value of a plurality of directions if desired; Then need a plurality of wheatstone bridge circuits structures, the volume ratio of entire device is bigger like this, is unfavorable for that equipment develops to the direction of miniaturization, intensification.

Summary of the invention

The object of the present invention is to provide a kind of circuit structure arrangement of anisotropic magnetoresistive device; Make the bridge diagram structure of Barber pole structure and Herringbone structure in the magnetic field value that can measure different directions; Can also reduce the volume of entire device, the equipment that is beneficial to develops to the direction of miniaturization, intensification.

The circuit structure of a kind of anisotropic magnetoresistive device of the present invention, it specifically comprises:

The first anisotropic magnetoresistive module that constitutes by first anisotropic magnetoresistive that is cascaded and second anisotropic magnetoresistive;

The second anisotropic magnetoresistive module that constitutes by the 3rd anisotropic magnetoresistive that is cascaded and the 4th anisotropic magnetoresistive;

Said first anisotropic magnetoresistive, second anisotropic magnetoresistive, the 3rd anisotropic magnetoresistive and the 4th anisotropic magnetoresistive constitute the wheatstone bridge circuits structure;

Be formed with conductive coil at said wheatstone bridge circuits structure periphery;

The said first anisotropic magnetoresistive module is vertical with the said second anisotropic magnetoresistive module, and the direction of the said first anisotropic magnetoresistive module institute measuring magnetic field is perpendicular to the direction of the second anisotropic magnetoresistive module institute measuring magnetic field.

The circuit structure of aforesaid anisotropic magnetoresistive device is controlled the increasing or subtract of resistance of said first anisotropic magnetoresistive, second anisotropic magnetoresistive, the 3rd anisotropic magnetoresistive and the 4th anisotropic magnetoresistive through controlling direction of current in the said conductive coil.

The present invention makes the anisotropic magnetoresistive device with specific circuit structure; Make the overall volume of anisotropic magnetoresistive device reduce and institute's measuring magnetic field is concentrated in the less zone; Thereby the anisotropic magnetoresistive device can be applied in other devices more neatly, to reach the purpose of device miniaturization, intensification.

Description of drawings

Fig. 1 is the vertical view synoptic diagram of the circuit structure of Barber pole structure proposed by the invention.

Fig. 2 is the vertical view synoptic diagram of the circuit structure of Herringbone structure proposed by the invention.

Fig. 3 is the reduced graph of circuit structure illustrated in figures 1 and 2.

Fig. 4, Fig. 5 are the reduced graph of the circuit structure shown in Figure 3 after the resistance variations.

Embodiment

Fig. 1 is the vertical view synoptic diagram of the circuit structure of Barber pole structure proposed by the invention; Wherein: rule separation and the bonding jumper 302 (exemplary marking) that is parallel to each other are deposited on above the ferrimagnet 301 (exemplary marking); And make every strip metal bar 302 become miter angle with the edge of ferromagnetic material 301; Because electric current can be along the shortest Distance Transmission; So electric current can pass through with the direction perpendicular to the bonding jumper edge in every pair of bonding jumper, and has just guaranteed that sense of current is to have become miter angle with the DOM of ferromagnetic material like this.Simultaneously, ferromagnetic material 301 is connected by bonding jumper 303.We also need be below entire device placement wire coil 300, wire coil 300 is to be used for galvanization to produce DOM that magnetic field keeps ferromagnetic material.

Fig. 2 is the vertical view synoptic diagram of the circuit structure of Herringbone structure proposed by the invention; As shown in Figure 2: entire device is assembled by many ferromagnetic thin film bars 401 (exemplary marking) that are parallel to each other; And ferromagnetic thin film bar 401 is connected by bonding jumper 402 (exemplary marking), and the angle that is become between ferromagnetic thin film bar 401 and the bonding jumper 302 is a miter angle.In this pattern; We need add external magnetic field generator; Make them before measuring the external magnetic field, to produce the magnetic field that is parallel to bonding jumper through a current impulse; Thereby make the DOM of ferromagnetic thin film of entire device all along the direction of bonding jumper, and then apply voltage at the two ends of ferromagnetic thin film and make electric current flow along the serpentine configuration of ferromagnetic material, so just can be so that sense of current has become miter angle with DOM.

In traditional anisotropic magnetoresistive device; In circuit structure illustrated in figures 1 and 2; Anisotropic magnetoresistive module 1 (3) is parallel with anisotropic magnetoresistive module 2 (4), makes anisotropic magnetoresistive module 1 (3) and anisotropic magnetoresistive module 2 (4) combine the magnetic field value of measuring some directions.The present invention makes anisotropic magnetoresistive module 1 (3) vertical with anisotropic magnetoresistive module 2 (4), and like this like Fig. 1 and Fig. 2, it is the magnetic field of x direction that anisotropic magnetoresistive module 1 (3) records, and anisotropic magnetoresistive module 2 (4) to record be the magnetic field of y direction.

Fig. 3 is the reduced graph of circuit structure illustrated in figures 1 and 2; Anisotropic magnetoresistive module 1 (3) is made up of anisotropic magnetoresistive 1a and anisotropic magnetoresistive 1b series connection; Anisotropic magnetoresistive module 2 (4) is made up of anisotropic magnetoresistive 2a and anisotropic magnetoresistive 2b series connection, and anisotropic magnetoresistive 1a, anisotropic magnetoresistive 1b, anisotropic magnetoresistive 2a and anisotropic magnetoresistive 2b constitute the wheatstone bridge circuits structure.We define: and the U=input voltage (+) – input voltage (-) and V=V output voltage (+) – output voltage (-), wherein: U is the input voltage that adds, and V is the output voltage of surveying.

Do not receiving external magnetic field to do the time spent, the initial resistance of each magnetic resistance is R.We are through external lead (not shown) around magnetic resistance; Positive and negatively control the positive and negative of ferromagnetic material DOM through what control direction of current in the external lead then; Thereby determined magnetic resistance to be increase or to have reduced Δ R; We have obtained two kinds of situation of Fig. 4 and Fig. 5 thus, and the Output Voltage Formula of said two kinds of situation is respectively:

(a)?V=U(ΔR1-ΔR2)/(2R)

(b)?V=U(-ΔR1-ΔR2)/(2R)

Through (a) and (b) two formula, we can try to achieve Δ R1 and Δ R2.And we know that resistance variations and externally-applied magnetic field value are linear, thereby can obtain the external magnetic field value of x and y direction.

Like this; We just can only measure the external magnetic field value of both direction with a bridge diagram structure; Generally need two bridge diagram structures just can measure the external magnetic field value of both direction in the conventional art; We can reduce the volume of entire device thus, are beneficial to device and develop to the direction of miniaturization, intensification.

As stated, under the situation that does not depart from spirit and scope of the invention, can also constitute many very embodiment of big difference that have.Should be appreciated that except like enclosed claim limited, the invention is not restricted at the instantiation described in the instructions.

Claims

1. A circuit structure of an anisotropic magnetoresistive device, characterized in that, comprising:

a first anisotropic reluctance module composed of a first anisotropic reluctance and a second anisotropic reluctance connected in series;

A second anisotropic reluctance module composed of a third anisotropic reluctance and a fourth anisotropic reluctance connected in series;

The first anisotropic magnetoresistance, the second anisotropic magnetoresistance, the third anisotropic magnetoresistance and the fourth anisotropic magnetoresistance form a Wheatstone bridge circuit structure;

a conductive coil formed around the Wheatstone bridge circuit structure;

The first anisotropic reluctance module is perpendicular to the second anisotropic reluctance module, and the direction of the magnetic field measured by the first anisotropic reluctance module is perpendicular to the second anisotropic reluctance module The direction of the magnetic field measured by the module.

2. The circuit structure of anisotropic magnetoresistive device as claimed in claim 1, is characterized in that, controls described first anisotropic magnetoresistance, second anisotropic magnetoresistance by controlling the electric current direction in described conductive coil The increase or decrease of the resistance values of the magnetoresistance, the third anisotropic magnetoresistance and the fourth anisotropic magnetoresistance.