Optimized extremely-large magnetic field measuring method and device
An optimized extremely-large magnetic field measuring method includes: placing four orthogonally configured tunneling magnetoresistive resistors into an externally applied magnetic field, acquiring the resistances of the tunneling magnetoresistive resistors; calculating the angle between a magnetization direction of a free layer of each tunneling magnetoresistive resistor and that of a reference layer on the basis of the resistances of the four resistors; calculating magnetic field intensity H 1 and direction θ 1 of the externally applied magnetic field calculating magnetic field intensity H 2 and direction θ 2 of the externally applied magnetic field; and determining final magnetic field intensity H 0 of the externally applied magnetic field on the basis of magnetic field intensity H 1 and of magnetic field intensity H 2 ; determining final direction θ of the externally applied magnetic field on the basis of direction θ 2 and of direction θ 1 ; and optimizing on the basis of direction θ and of magnetic field intensity H 0 .
1. A method for measuring magnetic field, comprising:
Step 1: placing four orthogonally configured tunneling magnetoresistive resistors into an externally applied magnetic field, and acquiring the resistance of each tunneling magnetoresistive resistor, wherein the first tunneling magnetoresistive resistor and the third tunneling magnetoresistive resistor are located in a first straight line, the second tunneling magnetoresistive resistor and the fourth tunneling magnetoresistive resistor are located in a second straight line, and the first straight line and the second straight line are perpendicular to each other;
Step 2: for each one of the four tunneling magnetoresistive resistors, calculating the angle between a magnetization direction of a free layer of the resistor and a reference layer of the resistor on the basis of the resistances of the resistor;
Step 3: calculating magnetic field intensity H 1 and direction θ 1 of the externally applied magnetic field on the basis of the angle between the free layer magnetization direction of and the reference layer magnetization direction of the first tunneling magnetoresistive resistor and of that of the third tunneling magnetoresistive resistor; calculating magnetic field intensity H 2 and direction θ 2 of the externally applied magnetic field on the basis of the angle between the free layer magnetization direction of and the reference layer magnetization direction of the second tunneling magnetoresistive resistor and of that of the fourth tunneling magnetoresistive resistor;
Step 4: determining final magnetic field intensity H 0 of the externally applied magnetic field on the basis of magnetic field intensity H 1 and of magnetic field intensity H 2 ; determining final direction θ 0 of the externally applied magnetic field on the basis of direction θ 2 and of direction θ 1 ; and
Step 5: optimizing magnetic field intensity H 0 on the basis of direction θ.
2. The method of claim 1 , wherein, in Step 2, an equation for calculating the angle between the magnetization direction of the free layer of each tunneling magnetoresistive resistor and that of the reference layer on the basis of the resistance of the tunneling magnetoresistive resistor is:
R=R avg [1-0.5 Δ max cos(φ F -φ R )];
wherein,
R avg =( R max +R min )/2,
Δ max =( R max −R min )/ R avg ,
R min is the resistance of the tunneling magnetoresistive resistor when the magnetization direction of the free layer and that of the reference layer are the same,
R max is the resistance of the tunneling magnetoresistive resistor when the magnetization direction of the free layer and that of the reference layer are opposite to each other,
φ F -φ R is the angle between the magnetization direction of the free layer of the tunneling magnetoresistive resistor and that of the reference layer; and
R is the resistance of the tunneling magnetoresistive resistor in the externally applied magnetic field.
3. The method of claim 1 , wherein, in Step 3, magnetic field intensity H 1 and direction θ 1 are calculated according to
{
θ
1
=
arctan
(
2
sin
φ
FR
1
sin
φ
FR
3
sin
(
φ
FR
3
-
φ
FR
1
)
)
H
1
=
H
BR
sin
(
φ
FR
1
+
φ
FR
3
)
sin
2
(
φ
FR
1
-
φ
FR
3
)
+
(
2
sin
φ
FR
1
sin
φ
FR
3
)
2
;
wherein,
H BR is the amplitude of the internal bias field of the reference layer of the four tunneling magnetoresistive resistors,
φ FR1 is the angle between the magnetization direction of the free layer and that of the reference layer of the first tunneling magnetoresistive resistor, and
φ FR3 is the angle between the magnetization direction of the free layer and that of the reference layer of the third tunneling magnetoresistive resistor, and
magnetic field intensity H 2 and direction θ 2 are calculated according to
{
θ
2
=
arctan
(
2
sin
φ
FR
2
sin
φ
FR
4
sin
(
φ
FR
4
-
φ
FR
2
)
)
H
2
=
H
BR
sin
(
φ
FR
2
+
φ
FR
4
)
sin
2
(
φ
FR
2
-
φ
FR
4
)
+
(
2
sin
φ
FR
2
sin
φ
FR
4
)
2
,
wherein,
H BR is the amplitude of the internal bias field of the reference layer of the four tunneling magnetoresistive resistors,
φ FR2 is the angle between the magnetization direction of the free layer of the second tunneling magnetoresistive resistor and that of the reference layer, and
φ FR4 is the angle between the magnetization direction of the free layer of the fourth tunneling magnetoresistive resistor and that of the reference layer.
4. The method of claim 1 , wherein, in Step 4,
H
0
=
H
1
=
H
2
,
and
θ
=
{
θ
1
,
θ
1
≥
0
,
θ
2
≥
0
-
θ
1
,
θ
1
≥
0
,
θ
2
<
0
θ
1
+
π
,
θ
1
<
0
,
θ
2
≥
0
-
θ
1
-
π
,
θ
1
<
0
,
θ
2
<
0
.
5. The method of claim 1 , wherein the intensity of the optimized externally applied magnetic field is H=kH 0 +b, wherein k and b are correction factors.
6. A device for measuring magnetic field, comprising:
a tunneling magnetoresistive resistor resistance acquiring module, for acquiring the resistances of the four tunneling magnetoresistive resistors orthogonally configured in the externally applied magnetic field,
wherein, the first tunneling magnetoresistive resistor and the third tunneling magnetoresistive resistor are located in a first straight line, the second tunneling magnetoresistive resistor and the fourth tunneling magnetoresistive resistor are located in a second straight line, and the first straight line and the second straight line are perpendicular to each other;
a tunneling magnetoresistive resistor free layer magnetization direction and reference layer magnetization direction angle calculating module for calculating the angle between the free layer magnetization direction for each one of the four tunneling magnetoresistive resistors and the corresponding reference layer thereof on the basis of the resistance thereof;
an externally applied magnetic field intensity and direction pre-calculating module, for calculating magnetic field intensity H 1 and direction θ 1 of the externally applied magnetic field on the basis of the angle between the free layer magnetization direction and the reference layer magnetization direction of the first tunneling magnetoresistive resistor and of that of the third tunneling magnetoresistive resistor, calculating field intensity H 2 and direction θ 2 of the externally applied magnetic field on the basis of the angle between the free layer magnetization direction and the reference layer magnetization direction of the second tunneling magnetoresistive resistor and of that of the fourth tunneling magnetoresistive resistor;
an externally applied magnetic field intensity and direction determining module, for determining final intensity H 0 of the externally applied magnetic field on the basis of magnetic field intensity H 1 and of magnetic field intensity H 2 , and determining final direction θ of the externally applied magnetic field on the basis of direction θ 2 and of direction θ 1 ; and
a magnetic field intensity optimizing module for optimizing magnetic field intensity H 0 on the basis of direction θ.
7. The device of claim 6 , wherein the tunneling magnetoresistive resistor free layer magnetization direction and reference layer magnetization direction angle calculating module, further wherein the equation for calculating the angle between the magnetization direction of the free layer of each tunneling magnetoresistive resistor and that of the reference layer on the basis of the resistances of the tunneling magnetoresistive resistors is as follows:
R=R avg [1-0.5Δ max cos(φ F -φ R )];
wherein,
R avg =( R max +R min )/2,
Δ max =( R max −R min )/ R avg ,
R min is the resistance of the tunneling magnetoresistive resistor when the magnetization direction of the free layer and that of the reference layer are the same,
R max is the resistance of the tunneling magnetoresistive resistor when the magnetization direction of the free layer and that of the reference layer are opposite,
φ F -φ R is the angle between the magnetization direction of the free layer and that of the reference layer of the tunneling magnetoresistive resistor, and
R is the resistance of the tunneling magnetoresistive resistor in the externally applied magnetic field.
8. The device of claim 6 ,
wherein magnetic field intensity H 1 and direction θ 1 are according to
{
θ
1
=
arctan
(
2
sin
φ
FR
1
sin
φ
FR
3
sin
(
φ
FR
3
-
φ
FR
1
)
)
H
1
=
H
BR
sin
(
φ
FR
1
+
φ
FR
3
)
sin
2
(
φ
FR
1
-
φ
FR
3
)
+
(
2
sin
φ
FR
1
sin
φ
FR
3
)
2
,
wherein,
H BR is the amplitude of the internal bias field of the reference layer of the four tunneling magnetoresistive resistors,
φ FR1 is the angle between the magnetization direction of the free layer and that of the reference layer of the first tunneling magnetoresistive resistor, and
φ FR3 is the angle between the magnetization direction of the free layer and that of the reference layer of the third tunneling magnetoresistive resistor; and
wherein magnetic field intensity H 2 and direction θ 2 are according to:
{
θ
2
=
arctan
(
2
sin
φ
FR
2
sin
φ
FR
4
sin
(
φ
FR
4
-
φ
FR
2
)
)
H
2
=
H
BR
sin
(
φ
FR
2
+
φ
FR
4
)
sin
2
(
φ
FR
2
-
φ
FR
4
)
+
(
2
sin
φ
FR
2
sin
φ
FR
4
)
2
,
wherein,
H BR is the amplitude of the internal bias field of the reference layer of the four tunneling magnetoresistive resistors,
φ FR2 is the angle between the magnetization direction of the free layer and that of the reference layer of the second tunneling magnetoresistive resistor, and
φ FR4 is the angle between the magnetization direction of the free layer and that of the reference layer of the fourth tunneling magnetoresistive resistor.
9. The device of claim 6 , wherein final intensity H 0 and final direction θ of the externally applied magnetic field are according to:
H
0
=
H
1
=
H
2
,
and
θ
=
{
θ
1
,
θ
1
≥
0
,
θ
2
≥
0
-
θ
1
,
θ
1
≥
0
,
θ
2
<
0
θ
1
+
π
,
θ
1
<
0
,
θ
2
≥
0
-
θ
1
-
π
,
θ
1
<
0
,
θ
2
<
0
.
10. The device of claim 6 , wherein magnetic field intensity H of the externally applied magnetic field is H=kH 0 +b, and k and b are correction factors.