Method for integrally detecting three-dimensional vector magnetic field based on excitation and reading

Abstract

The invention relates to the field of magnetic field detection, and discloses a method for integrally detecting a three-dimensional vector magnetic field based on excitation and reading, a spin-orbit torque device sensor is adopted, a ferromagnetic material of the sensor has zero residual magnetism and perpendicular magnetic anisotropy, and the method comprises the following steps: applying excitation current to the sensor, and reading output voltage at the same time; obtaining R-H curves of an independent x-direction magnetic field, an independent y-direction magnetic field and an independent z-direction magnetic field; the sensor is placed in a magnetic field to be measured, information of each component of a magnetic field vector is solved through operation by changing the polarity and direction of pulse current, and the size and direction of an unknown magnetic field are obtained according to three components obtained in three directions. Under the combined action of the spin-orbit torque in the sensor, the anisotropic field of the magnetic layer of the zero-remanence magnet, the demagnetizing field and the applied external magnetic field, the write-in and read operations are completed at the same time under the driving of the pulse current, and the function of rapidly and accurately measuring the three-dimensional magnetic field by a single device can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field related to magnetic field detection, and more specifically, relates to a method for detecting a three-dimensional vector magnetic field based on integrated excitation and reading. Background Art

[0002] A magnetic field sensor is a device that detects the magnitude and direction of a magnetic field intensity and converts it into an electrical signal. Currently, it has very wide applications. Based on magnetic field sensors, various sensing functions can be developed, including current, power, position, distance, speed, angle, etc. It has been widely used in the fields of industrial manufacturing, precision measurement, national defense and aviation, medical treatment, geography, etc., and has a continuously broad application space.

[0003] Currently, commonly used magnetic sensors include anisotropic magnetoresistive sensors, magnetosensitive diodes, Hall sensors, fluxgate magnetometers, etc., which can detect the direction or intensity of a magnetic field, but all have some limitations. For example, anisotropic magnetoresistive sensors have low measurement accuracy and require a supporting calibration algorithm; fluxgate magnetometers are large in size and high in cost; magnetosensitive diodes have low sensitivity, and the signal output is only about 0.05 mV / Oe, and signal amplification and other modules need to be matched.

[0004] In addition, the most commonly used magnetic sensing technologies currently are Hall sensors, magnetic tunnel junction sensors based on the tunneling magnetoresistance effect, quantum color center sensors based on nitrogen vacancies, and magnetic sensors based on superconducting quantum interferometers. Hall sensors have a simple structure and a wide measurement range, but they need to be above the micron level in size to achieve more sensitive magnetic field detection. A single magnetic tunnel junction sensor can achieve a sub-micron size and sufficient sensitivity, but since such a magnetic sensor can only measure the magnetic field intensity in a single direction for a single device, generally three devices need to be combined for measurement when measuring a three-dimensional magnetic field, which will be more complex, greatly increase the size, and introduce errors. Although magnetic sensors based on superconducting quantum interferometers have currently achieved nanoscale magnetic field detection, they can only measure one-dimensional magnetic fields, and superconducting materials need to work at very low temperatures, and low-temperature facilities also greatly increase the volume and complexity of the equipment. Quantum magnetic sensors based on nitrogen vacancies sense the magnetic field through quantum color centers, have the highest current spatial resolution, and also have extremely high sensitivity, but generally require complex optical and microwave equipment for assistance during use, have a relatively complex structure, and cannot be integrated into portable devices and integrated circuit chips. In addition, since the nitrogen vacancy color centers used for testing are generally generated at random positions by irradiation, the characteristics of different devices are also random, which is not suitable for array integration. Therefore, it has certain limitations.

[0005] In the field of scientific research, magnetic sensors based on heavy metal / ferromagnetic thin film heterojunctions can measure the three-dimensional magnetic field vector of a single device through the relationship between the movement or nucleation of magnetic domain walls and the external magnetic field. However, the working mode with separated drive current and read current results in a slower response time. In addition, under this working mode, the power consumption and noise level obtained through characterization cannot reflect the actual working conditions. Summary of the Invention

[0006] In view of the above defects or improvement requirements of the prior art, the present invention provides a method for detecting a three-dimensional vector magnetic field based on integrated excitation and reading, aiming to use a spin-orbit torque device sensor with a ferromagnetic material having zero remanence and perpendicular magnetic anisotropy. When an excitation current is applied to the sensor and the output voltage is read out simultaneously for calibration, and then the sensor is placed in the magnetic field to be measured. By changing the polarity and direction of the pulsed current, the information of each component of the magnetic field vector is solved through calculation, and the magnitude and direction of the magnetic field to be measured are obtained, thereby solving the technical problem of slow response caused by the separation of the drive current and the read current in the prior art.

[0007] To achieve the above object, according to the first aspect of the present invention, a method for detecting a three-dimensional vector magnetic field based on integrated excitation and reading is provided. A spin-orbit torque device sensor is used, and the ferromagnetic material of the spin-orbit torque device sensor has zero remanence and perpendicular magnetic anisotropy. A three-dimensional rectangular coordinate system is calibrated with the directions of two mutually orthogonal electrodes in the plane of the spin current generation layer as the x-axis and y-axis, and the direction perpendicular to the surface of the spin current generation layer as the z-axis, including the following steps:

[0008] S1. Calibrate the sensor with a magnetic field of known magnitude and direction: Apply an excitation current to the sensor to generate a spin-polarized current in the spin current generation layer, apply a spin-orbit torque to the zero-remanence ferromagnetic layer. Under the combined action of the spin-orbit torque, the anisotropy field, the demagnetization field, and the applied external magnetic field of the zero-remanence ferromagnetic layer, the magnetic moment of the zero-remanence ferromagnetic layer reaches a stable state regulated by the external magnetic field. At the same time, read out the output voltage to obtain the R-H curves of the magnetic fields in the x direction, y direction, and z direction alone.

[0009] S2. Place the sensor in the magnetic field to be measured, apply the same positive and negative excitation currents as in S1 in the x direction, and measure the output voltage in the y direction simultaneously to obtain the resistance values R1 and R2. Since the net contributions of different magnetic field components to the resistance are independent, calculate the contributions R Hx and R Hz of the magnetic field components in the x-axis and z-axis to the resistance respectively, and substitute them into the R-H curves of the magnetic fields in the corresponding directions to obtain the magnetic field components H x and H z ;

[0010] S3. Keep the position of the sensor unchanged, apply positive and negative excitation currents in the y direction that are the same as those in S1 respectively, and measure the output voltage in the x direction simultaneously to obtain two resistance values R3 and R4; calculate the contribution R of the magnetic field in the y-axis to the resistance based on the resistance values R3 and R4 Hy , substitute it into the R-H curve of the magnetic field in the y direction to obtain the magnetic field component H y ;

[0011] S4. Calculate the magnitude and direction of the unknown magnetic field according to the three components H x 、H y 、H z measured in the x, y, and z directions of the magnetic field to be measured

[0012] Preferably, in step S1, the magnitude of the excitation current is 0.1 - 2.5 mA, and the pulse width is 30 ns - 50 μs

[0013] Preferably, the spin-orbit torque device sensor includes a sensor of a cross-shaped Hall Bar structure device or a sensor of a tunnel junction device; wherein the ferromagnetic material serves as the magnetic layer in the cross-shaped Hall Bar structure device and as the free layer in the tunnel junction device

[0014] Preferably, the four ends of the sensor of the cross-shaped Hall Bar structure device are successively the first electrode, the second electrode, the third electrode, and the fourth electrode of the device. The direction from the first electrode to the third electrode is the positive direction of the x-axis, and the direction from the fourth electrode to the second electrode is the positive direction of the y-axis; or, the direction from the second electrode to the fourth electrode is the positive direction of the x-axis, and the direction from the first electrode to the third electrode is the positive direction of the y-axis

[0015] The five ends of the sensor of the tunnel junction device structure are successively the first electrode, the second electrode, the third electrode, the fourth electrode, and the upper electrode of the device. The direction from the first electrode to the third electrode is the positive direction of the x-axis, and the direction from the fourth electrode to the second electrode is the positive direction of the y-axis

[0016] Preferably, calibrate the sensor based on the cross-shaped Hall Bar structure device: apply an excitation current to the first electrode and the third electrode, and measure the output voltage at the second electrode and the fourth electrode simultaneously, or apply an excitation current to the second electrode and the fourth electrode, and measure the output voltage at the first electrode and the third electrode simultaneously

[0017] Calibrate the sensor based on the tunnel junction device structure: Apply an excitation current to the first electrode and the third electrode, or the second electrode or the fourth electrode among them, and simultaneously measure the resistance between the third electrode and the upper electrode.

[0018] As a preference of the present invention, in step S1, when applying an excitation current to the sensor and simultaneously reading out the output voltage to obtain the R-H curves of the magnetic field in the separate x direction, the magnetic field in the separate y direction, and the magnetic field in the separate z direction, it specifically includes the following steps:

[0019] S101. Place the sensor in a magnetic field with a changing magnitude H x in the x direction. Apply a positive current in the x direction and simultaneously measure the output voltage in the y direction. Divide the voltage by the positive current to obtain the resistance R + , and obtain the R + -H x curve under the positive current of the separate x magnetic field; Apply a negative current with the same magnitude in the x direction and simultaneously measure the output voltage in the y direction. Divide the voltage by the negative current to obtain the resistance R - , and obtain the R - -H x curve under the negative current of the separate x magnetic field; Calculate the net contribution R of the magnetic field in the x direction to the resistance through the measured R + and R - under the same magnitude of the magnetic field in the x direction. R = (R + -R - ) / 2, and obtain the R-H x curve of the separate x magnetic field;

[0020] S102. Place the sensor in a magnetic field with a changing magnitude H z in the z direction. Apply a positive current with the same magnitude in the x direction and simultaneously measure its voltage in the y direction. Divide the voltage by the positive current to obtain the resistance R + , and obtain the R + -H z curve under the positive current of the separate z magnetic field; Apply a negative current with the same magnitude in the x direction and measure its voltage in the y direction. Divide the voltage by the negative current to obtain the resistance R - , and obtain the R-H z curve under the negative current of the separate z magnetic field; Calculate the net contribution R of the magnetic field in the x direction to the resistance through the measured R + and R - under the same magnitude of the magnetic field in the z direction. R = (R + -R - ) / 2, and obtain the R-H z curve of the separate z magnetic field;

[0021] S103. Place the sensor in a magnetic field with a changing magnitude H yIn a magnetic field with a change and a direction along the y-axis, a positive current of the same magnitude is applied in the y-direction, and the output voltage is measured in the x-direction. The voltage is divided by the positive current to obtain the resistance R. + , obtaining R under a positive current in a magnetic field along the y-axis alone. + -Hy curve; a negative current of the same magnitude is applied in the y-direction, and its voltage is measured in the x-direction. The voltage is divided by the negative current to obtain the resistance R. - , obtaining R-H under a negative current in a magnetic field along the y-axis alone. y curve; through the R + and R - measured under the same magnitude of the magnetic field in the y-direction, calculate the net contribution R of the magnetic field in the y-direction to the resistance, R = (R + - R - ) / 2, obtaining the R-H y curve under a magnetic field along the y-axis alone.

[0022] As a preference of the present invention, in step S2, calculating the contributions R Hx and R Hz of the magnetic field components along the x-axis and z-axis to the resistance respectively based on the resistance change, and substituting them into the R-H curves of the magnetic fields in the corresponding directions to obtain the magnetic field components H x and H z , including:

[0023] Calculating the contribution value R Hz of the magnetic field along the z-axis alone to the resistance and the contribution value R Hx of the magnetic field along the x-axis alone to the resistance based on the resistance values R1 and R2, R Hz = (R1 + R2) / 2; R Hx = (R1 - R2) / 2;

[0024] Substituting the contribution value R Hx into the R-H x curve under a magnetic field along the x-axis alone to obtain the x-direction component H x of the magnetic field to be measured; substituting the contribution value R Hz into the R-H z curve under a magnetic field along the z-axis alone to obtain the z-direction component H z of the magnetic field to be measured.

[0025] As a preference of the present invention, in step S3, calculating the contribution value R Hy of the magnetic field along the y-axis alone to the resistance based on the resistance values R3 and R4, R Hy = (R3 - R4) / 2; substituting the contribution value R Hy into the R-H y curve under a magnetic field along the y-axis alone to obtain the y-direction component H y of the magnetic field to be measured.

[0026] Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention mainly have the following technical advantages:

[0027] 1. The method for detecting a three-dimensional vector magnetic field based on integrated excitation and reading disclosed by the present invention uses a spin-orbit torque device sensor with a zero-remnant magnetized magnetic layer, and includes the following steps: applying an excitation current to the sensor while reading out the output voltage to obtain the R-H curves of the magnetic fields in the separate x-direction, separate y-direction, and separate z-direction; placing the sensor in the magnetic field to be measured, and by changing the polarity and direction of the pulsed current, the information of each component of the magnetic field vector can be solved by simple calculation, and the magnitude and direction of the unknown magnetic field can be obtained based on the three components obtained in the three directions. The present invention relies on the combined action of the spin-orbit torque in the sensor with the anisotropy field, demagnetization field of the zero-remnant magnetized magnetic layer, and the applied external magnetic field, and the write and read operations are simultaneously completed by the pulsed current drive, realizing the function of quickly and accurately measuring the three-dimensional magnetic field with a single device.

[0028] 2. Preferably, due to the special magnetization dynamics mechanism of the zero-remnant magnetized magnetic layer that enables the magnetic moment of the ferromagnetic layer to reach a steady state under the excitation current, the magnitude of the excitation current of the present invention is 0.1 to 2.5 mA, and the pulse width is 30 ns to 50 μs. Compared with the prior art where the pulse width of the write current is above 0.1 s, the magnitude is above 32 mA, and the read current is 0.1 mA, the method of the present invention realizes the steps of simultaneously completing writing and reading, reduces the working power consumption of the sensor, and also improves the rapidity and accuracy of measurement due to the special magnetization dynamics mechanism and integrated excitation and reading.

[0029] 3. Preferably, the spin-orbit torque device sensor of the present invention with a zero-remnant magnetized magnetic layer is a cross-shaped Hall Bar structure device based on magnetic material systems such as CoFeB / MgO, Co / Pt multi-layer films, or a tunnel junction device based on magnetic tunneling material systems such as CoFeB / MgO / CoFeB. That is, in practical applications, the three-dimensional magnetic field vector sensor proposed in this paper can achieve on-chip integration at the micron or even nanometer scale, and can be replaced with a tunnel junction structure to improve performance, realizing three-dimensional magnetic field vector measurement on a single sensor with a small area overhead, with a simple structure avoiding the problem of non-orthogonality of complex systems and better realizing efficient operation.

[0030] 4. Preferably, based on the ferromagnetic thin film with the structure of W / CoFeB / MgO / TiO, the three-dimensional magnetic field vector sensor at the micron size level is prepared by utilizing the physical characteristics of the relevant effects generated by the device through the anomalous Hall effect and the spin-orbit torque effect under a three-dimensional magnetic field. By measuring the change curves of the anomalous Hall resistance values in three orthogonal directions and the magnitude of the magnetic field, the corresponding relationships between the magnitudes of the magnetic fields in the three orthogonal directions and the anomalous Hall resistances generated by them are established. The curves have good linearity and high goodness of fit. Through performance evaluation, it shows that the above thin film structure has good remanence characteristics and perpendicular magnetic anisotropy. The three-dimensional magnetic field vector sensor has good repeat test performance, measurement durability, high measurement accuracy, and a wide measurement range. Driven by pulsed current, the function of simultaneous reading and writing is realized, and the simultaneous reading and writing operation of the three-dimensional magnetic field sensor based on the anomalous Hall effect and the spin-orbit torque effect is achieved, and the power consumption is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the structure of the three-dimensional magnetic field vector sensor according to an example of the present invention.

[0032] Figure 2 Optical microscope image of the device according to an example of the present invention.

[0033] Figure 3 Curve of the anomalous Hall resistance of the device according to an example of the present invention changing with the perpendicular magnetic field.

[0034] Figure 4 is R xy as H z , H x and H y functions, changes at I x = +2.5 mA and -2.5 mA, where Figure 4 in a is the curve of R xy as H z function curve, c is the curve of R xy as H x function curve, e is the curve of R xy as H y function curve; R yx as (b) H z , (d) H x and (f) H y functions, changes at I y = +2.5 mA and -2.5 mA, where Figure 4 in b is the curve of R yx as H z function curve, d is the curve of R yx as H xThe function curve of, where f is in R yx As H y The function curve; The magnetic field is scanned forward and backward in each direction, ranging from -100 to +100 Oe.

[0035] Figure 5 Is composed of H x 、H y 、H z The relationship between the net resistance component contributed by and the change of the net resistance; where Figure 5 In, a is the relationship between the net resistance component R(H z ) and the change of H z , b is the relationship between the net resistance component R(H x ) and the change of H x , c is the relationship between the net resistance component R(H y ) and the change of H y .

[0036] Figure 6 Is the noise spectrum of the device, at the write current I = 2.5 mA, The relationship with frequency. Detailed implementation manners

[0037] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] To achieve the mousse of the present invention, a method for detecting an unknown three-dimensional vector magnetic field based on integrated excitation and reading is provided, which is applied to a spin-orbit torque device sensor with a ferromagnetic material having zero remanence and perpendicular magnetic anisotropy. A three-dimensional rectangular coordinate system is calibrated with the directions of two mutually orthogonal electrodes in the surface of the spin current generation layer as the x-axis and the y-axis, and the direction perpendicular to the surface of the spin current generation layer as the z-axis. The method specifically includes the following steps:

[0039] S1. Calibrate the vector magnetic field sensor with a magnetic field of known magnitude and direction. Apply a small excitation current to the sensor of the spin-orbit torque device with a ferromagnetic layer having zero remanence characteristics, and simultaneously read out the output voltage to obtain the R-H curves of the magnetic field in the separate x-direction, separate y-direction, and separate z-direction. Among them, for the sensor of the present invention, when a positive excitation current is applied in the x-direction, a spin-polarized current is generated in the spin current generation layer, and a spin-orbit torque effect is applied to the ferromagnetic layer; at the same time, the spin-orbit torque acts jointly with the special anisotropy field, demagnetizing field, and external magnetic field of the zero-remanence ferromagnetic layer, so that the magnetic moment of the zero-remanence ferromagnetic layer reaches a stable state regulated by the external magnetic field, rather than reaching the final state through magnetization precession after the excitation current is removed. Therefore, when a positive excitation current is applied in the x-direction, while the magnetic moment reaches a stable state, the voltage is measured in the y-direction, and the application of the excitation current and the measurement of the voltage are carried out simultaneously.

[0040] S2. Place the sensor in a magnetic field to be measured with unknown magnitude and direction;

[0041] Apply the same positive excitation current in the x-direction as in the calibration process in step S1, and simultaneously measure the output voltage in the y-direction. Divide the voltage by the current to obtain the resistance value R1;

[0042] Keep the position of the vector magnetic field sensor unchanged. Apply the same negative excitation current in the x-direction as in the calibration process in step S1, measure the voltage in the y-direction, and divide the voltage by the current to obtain the resistance value R2;

[0043] Calculate the contribution value R of the magnetic field component in the z-direction of the unknown vector magnetic field to the resistance Hz and the contribution value R of the magnetic field component in the x-direction of the unknown vector magnetic field to the resistance Hx ;

[0044] Substitute the contribution values R Hx and R Hz into the R-H curves of the separate x-direction magnetic field and separate z-direction magnetic field obtained in the calibration process in step S1 respectively, to obtain the x-direction component H x and z-direction component H z of the unknown vector magnetic field;

[0045] S3. Keep the position of the sensor unchanged in the magnetic field to be measured;

[0046] Apply the same positive excitation current and negative excitation current as in the calibration process in step S1 in the y-direction respectively, and simultaneously measure the output voltage in the x-direction to obtain two resistance values R3 and R4;

[0047] Based on the resistance values R3 and R4, calculate the contribution value R of the magnetic field component in the y-direction of the unknown vector magnetic field to the resistanceHy ;

[0048] Substitute the contribution value R Hy into the R-H curve of the separately measured y-direction magnetic field obtained in the calibration process in step S1 to obtain the y-direction component H of the unknown vector magnetic field y ;

[0049] From the three components H x 、H y 、H z of the unknown vector magnetic field in the x, y, and z directions, calculate the magnitude and direction of the unknown magnetic field.

[0050] In some embodiments, in step S1, while applying a current, measure the output voltage, and the magnitude of the applied excitation current is 0.1 - 2.5 mA, and the pulse width is 30 ns - 50 μs.

[0051] In some embodiments, the spin-orbit torque device sensor includes a sensor of a cross-shaped Hallbar structure device or a sensor of a tunnel junction device; wherein a ferromagnetic material with zero remanence characteristics and perpendicular magnetic anisotropy serves as the magnetic layer in the cross-shaped Hall Bar structure device and as the free layer in the tunnel junction device.

[0052] In some embodiments, the four ends of the sensor of the cross-shaped Hall Bar structure device are successively the first electrode, the second electrode, the third electrode, and the fourth electrode of the device. The direction from the first electrode to the third electrode is defined as the positive direction of the x-axis, and the direction from the fourth electrode to the second electrode is defined as the positive direction of the y-axis; or, the direction from the second electrode to the fourth electrode is defined as the positive direction of the x-axis, and the direction from the first electrode to the third electrode is defined as the positive direction of the y-axis;

[0053] The five ends of the sensor based on the tunnel junction device structure are successively the first electrode, the second electrode, the third electrode, the fourth electrode, and the upper electrode of the device. The direction from the first electrode to the third electrode is defined as the positive direction of the x-axis, and the direction from the fourth electrode to the second electrode is defined as the positive direction of the y-axis.

[0054] In some embodiments, step S1 includes the following steps:

[0055] S101. A vector magnetic field sensor based on a cross-shaped Hall Bar structure is placed in a magnetic field with a magnitude H x changing and a direction in the x direction. Apply a positive current in the x direction and measure the voltage in the y direction. Divide the voltage by the positive current to obtain the resistance R + , and obtain R + -H xA curve; A vector magnetic field sensor based on a tunnel junction device structure is placed in a magnetic field with a varying magnitude Hx in the x - direction. A positive current is applied in the x - direction, and the resistance R between the third electrode and the fifth electrode is measured simultaneously. + , obtaining the R - H curve under a positive current in the x - magnetic field alone. + -H x curve;

[0056] A vector magnetic field sensor based on a cross - shaped Hall Bar structure is placed in a magnetic field with a varying magnitude H in the x - direction. A negative current of the same magnitude is applied in the x - direction, and its voltage is measured in the y - direction. The voltage divided by the negative current gives the resistance R. x , obtaining the R - H curve under a negative current in the x - magnetic field alone. - , obtaining the R - H curve under a negative current in the x - magnetic field alone. - -H x A curve; A vector magnetic field sensor based on a tunnel junction device structure is placed in a magnetic field with a varying magnitude H in the x - direction. A negative current is applied in the x - direction, and the resistance R between the third electrode and the fifth electrode is measured simultaneously. x , obtaining the R - H curve under a negative current in the x - magnetic field alone. - , obtaining the R - H curve under a negative current in the x - magnetic field alone. - -H x curve;

[0057] The net contribution R of the magnetic field in the x - direction to the resistance is calculated from the measured R and R at the same magnitude of the magnetic field in the x - direction as follows: R=(R - R) / 2, obtaining the R - H curve under the magnetic field in the x - direction alone. + and R - Specifically as follows: R = (R - R) / 2, obtaining the R - H curve under the magnetic field in the x - direction alone. + -R - ) / 2, obtaining the R - H curve under the magnetic field in the x - direction alone. x curve.

[0058] S102. A vector magnetic field sensor based on a cross - shaped Hall Bar structure is placed in a magnetic field with a varying magnitude H in the z - direction. A positive current of the same magnitude is applied in the x - direction, and its voltage is measured in the y - direction. The voltage divided by the positive current gives the resistance R. z , obtaining the R - H curve under a positive current in the z - magnetic field alone. + , obtaining the R - H curve under a positive current in the z - magnetic field alone. + -H z A curve; A vector magnetic field sensor based on a tunnel junction device structure is placed in a magnetic field with a varying magnitude H in the z - direction. A positive current is applied in the x - direction, and the resistance R between the third electrode and the upper electrode is measured simultaneously. z , obtaining the R - H curve under a positive current in the z - magnetic field alone. + , obtaining the R - H curve under a positive current in the z - magnetic field alone. + -H z curve;

[0059] A vector magnetic field sensor based on a cross - shaped Hall Bar structure is placed in a magnetic field with a varying magnitude H in the z - direction. zIn a magnetic field with a change and a z - direction, a negative current of the same magnitude is applied in the x - direction, and its voltage is measured in the y - direction. The resistance R is obtained by dividing the voltage by the negative current. - to obtain R under a negative current in a magnetic field of z alone - -H z curve; A vector magnetic field sensor based on a tunnel - junction device structure is placed in a magnetic field with a magnitude H z changing and a z - direction. A negative current is applied in the x - direction, and the resistance R between the third electrode and the upper electrode is measured simultaneously. - to obtain R under a negative current in a magnetic field of z alone - -H z curve;

[0060] For a vector magnetic field sensor based on a cross - shaped Hall Bar structure, the net contribution R of the magnetic field in the x - direction to the resistance is calculated through the measured R + and R - under the same magnitude of the magnetic field in the z - direction, as follows: R=(R + +R - ) / 2, to obtain the R - H z curve under a magnetic field of z alone.

[0061] S103. A vector magnetic field sensor based on a cross - shaped Hall Bar structure is placed in a magnetic field with a magnitude H y changing and a y - direction. A positive current of the same magnitude is applied in the y - direction, and its voltage is measured in the x - direction. The resistance R is obtained by dividing the voltage by the positive current. + to obtain R under a positive current in a magnetic field of y alone + -H y curve; A vector magnetic field sensor based on a tunnel - junction device structure is placed in a magnetic field with a magnitude H y changing and a y - direction. A positive current is applied in the y - direction, and the resistance R between the third electrode and the upper electrode is measured simultaneously. + to obtain R under a positive current in a magnetic field of y alone + -H y curve;

[0062] A vector magnetic field sensor based on a cross - shaped Hall Bar structure is placed in a magnetic field with a magnitude H y changing and a y - direction. A negative current of the same magnitude is applied in the y - direction, and its voltage is measured in the x - direction. The resistance R is obtained by dividing the voltage by the negative current. - to obtain R under a negative current in a magnetic field of y alone - -H y curve; A vector magnetic field sensor based on a tunnel - junction device structure is placed in a magnetic field with a magnitude H y changing and a y - direction. A negative current is applied in the y - direction, and the resistance R between the third electrode and the fifth electrode is measured simultaneously. -, obtain R under a single negative y - magnetic - field current - -H y curve;

[0063] Calculate the net contribution R of the x - direction magnetic field to the resistance from the measured R + and R - as follows: R=(R + -R - ) / 2. Obtain the R - H y curve under a single y - magnetic field.

[0064] In some embodiments, based on the resistance values R1 and R2, calculate the contribution value R Hz of the single z - direction magnetic field to the resistance and the contribution value R Hx of the single x - direction magnetic field to the resistance, as follows: R Hz =(R1 + R2) / 2; R Hx =(R1 - R2) / 2.

[0065] Substitute the contribution values R Hx , R Hz into the R - H curves of the single x - magnetic field and the single z - magnetic field respectively, to obtain the x - direction component H x and the z - direction component H z of the magnetic field to be measured. Specifically, including: if R Hx =(R1 - R2) / 2, then substitute the contribution value R Hx into the R - H x curve under the single x - magnetic field to obtain the x - direction component H x of the unknown magnetic field.

[0066] Substitute the contribution value R Hz into the R - H z curve under the single z - magnetic field to obtain the z - direction component H z of the unknown magnetic field.

[0067] In some embodiments, based on the resistance values R3 and R4, calculate the contribution value R Hy of the single y - direction magnetic field to the resistance, as follows: R Hy =(R3 - R4) / 2; then substitute the contribution value R Hy into the R - H curve of the single y - magnetic field to obtain the y - direction component Hy of the unknown magnetic field. Specifically, including: if R Hy =(R3 - R4) / 2, substitute the contribution value R Hy into the R - H y curve under the single y - magnetic field to obtain the y - direction component H y of the unknown magnetic field.

[0068] In some embodiments, step S1 of applying a current and reading a voltage is performed simultaneously. For a vector magnetic field sensor based on a cross-shaped Hall Bar structure, a small excitation current is applied to the device while measuring the output voltage. For a vector magnetic field sensor based on a tunnel junction device structure, a small excitation current is applied to the device while measuring the resistance between the third electrode and the fifth electrode.

[0069] To further illustrate the device provided by the present invention, the following further details the specific embodiments of the present invention in conjunction with the accompanying drawings, so that the technical solutions of the present invention are easier to understand and master.

[0070] The following provides a sensor for applying the detection method of the present invention. The sensor is a magnetic sensor device for measuring the magnetic field vector in a three-dimensional space based on the relationship between the magnetic moment orientation and the external magnetic field.

[0071] An integrated three-dimensional magnetic field vector sensor based on the spin-orbit torque effect. The hetero-junction magnetic multi-layer film material used is a widely used perpendicular magnetic anisotropy ferromagnetic thin film, which is prepared by ultra-high vacuum magnetron sputtering. A bottom spin current generation layer, a magnetic material layer, a barrier layer, and a top capping layer are sequentially grown on an Al2O3 substrate.

[0072] As Figure 1 shown, it is a schematic structural diagram of a three-dimensional magnetic field vector sensor according to an example of the present invention, including an Al2O3 substrate, a bottom spin current generation layer, a strong magnetic material layer, a barrier layer, and a top capping layer are sequentially arranged on the Al2O3 substrate; wherein, the bottom spin current generation layer is a heavy metal W layer, the strong magnetic material layer is a CoFeB layer, the barrier layer is a MgO insulating layer, and the top capping layer is a TiO heavy metal layer.

[0073] The thickness of the bottom spin current generation layer is 4 nm; the thickness of the magnetic material layer is 1.2 nm; the thickness of the barrier layer is 2 nm; the thickness of the top capping layer is 1 nm. Among them, the magnetic material layer CoFeB layer is obtained by sequentially magnetron sputtering and growing W / CoFeB / MgO / TiOx on an alumina substrate using a high-vacuum magnetron sputtering coating system, and annealing at 330 °C for 1 hour after growth.

[0074] A Hall Bar structure of a "cross-shaped" four-terminal device is designed, and a double-sided exposure photolithography mask template matching it is designed, and the above ferromagnetic thin film is processed by micro-nano processing technology to prepare an angle sensor.

[0075] The above-mentioned micro-nano processing technology first uses acetone, ethanol, and deionized water to ultrasonically clean the above-mentioned ferromagnetic thin film in sequence. Subsequently, a spin coater is used to spin-coat photoresist on the above-mentioned cleaned thin film, and the above-mentioned thin film is pre-baked on a hot plate. After contact exposure using an ultraviolet lithography machine, a developer is used for development to obtain the photolithography pattern corresponding to the above-mentioned cross-shaped Hall Bar structure. Then, an ion beam etching machine is used for etching. The photoresist-covered area is not affected by etching, and the area not covered by the photoresist is etched to the substrate. Finally, acetone is used to remove the photoresist on the surface of the device, obtaining the above-mentioned designed cross-shaped Hall Bar device. The optical micrograph of the sensor device is as shown in Figure 2 shown, and the core size of the device is 50×80μm 2 , and the size of the four electrode parts is 100×100μm 2 .

[0076] The resistance of the device is related to the magnetization direction of the ferromagnetic layer, and the anomalous Hall resistance RH is used to characterize the magnetization state of the device. During testing, mainly the anomalous Hall effect test is carried out. A test current is passed through both ends of the device, and the anomalous Hall voltage is measured at the other two ends. The anomalous Hall resistance of the device can be obtained through calculation. By measuring the variation relationship of the anomalous Hall resistance (RH) with the magnetic field in three orthogonal directions.

[0077] For the three-dimensional magnetic field vector sensor based on the above-mentioned cross-shaped Hall Bar structure, the device is fixed on a ceramic test board, and four-terminal electrodes are led to an anomalous Hall effect test system for the anomalous Hall effect test, specifically as follows:

[0078] First, a magnetic field is applied in the z direction shown in Figure 1 , that is, the vertical direction of the device, through an electromagnet. Then, a test current is passed through both ends of the device, and the anomalous Hall voltage is measured at the other two ends. The anomalous Hall resistance of the device can be obtained through calculation; as shown in Figure 3 . Generally, the Hall effect of magnetic materials includes two parts: the normal Hall effect and the anomalous Hall effect. In the test of ferromagnetic materials, the signal generated by the AHE is much larger than the signal generated by the normal Hall effect, and the anomalous Hall resistance is only related to the material, temperature, and perpendicular magnetization intensity. Therefore, when the material and temperature remain unchanged, the anomalous Hall resistance is only related to the perpendicular magnetization intensity. Based on this characteristic, measuring R H is used to study the magnetic perpendicular film.

[0079] This device has strong perpendicular magnetic anisotropy (PMA), its easy axis is oriented out of the plane, and the z direction shows superparamagnetic behavior, that is, there is no remanent magnetic hysteresis loop, as shown in Figure 3 . When taking Figure 1When a driving current is applied in one of the cross paths in a certain way, under the combined action of an external magnetic field, a spin-orbit torque (SOT) effective field, a demagnetizing field, and PMA, the overall magnetic moment of the magnetic layer will be reoriented, and an anomalous Hall voltage proportional to the z-direction magnetic moment component will be generated in the other path. Thus, the read operation is completed during the write process, that is, the read-write integrated operation. Compared with other three-dimensional magnetic field sensors based on the anomalous Hall effect, this invention example does not require applying a large write current followed by a read current, achieving the read-write integrated operation and greatly improving the operation speed. Theoretically, it can reach the operation speed required for magnetic moment flipping, that is, at the nanosecond level.

[0080] The three-dimensional magnetic field H consists of two in-plane magnetic field components (H x or H y ) and an out-of-plane magnetic field component (H z ). The application of H z can adjust the magnetization state of the device due to the perpendicular magnetic anisotropy (PMA) of the device. Under the action of positive and negative currents, R xy will be affected by the magnetic field direction but is independent of the current direction, as shown by a and b in Figure 4 . Therefore, the R xy -H z curves under positive and negative currents completely overlap. As shown by c in Figure 4 , the R xy -H x curves under positive and negative currents are symmetric about the x-axis. For example, under positive H x , when I x = +2.5 mA, a positive spin-orbit torque (SOT) effective field will be generated, resulting in a positive R xy . In contrast, when I x = -2.5 mA, the value of R xy is reversed. On the contrary, when the applied current direction is perpendicular to the magnetic field, the anomalous Hall resistance value remains almost constant, as shown by d in Figure 4 . In addition, when an appropriate current is applied, there is a linear relationship between R xy and H x . As can be seen from c in Figure 4 , within an appropriate H x range, R xy varies linearly with H x . Due to the equivalence of the x and y directions in the device, the variation of R yx with respect to H y exhibits the same characteristics as the variation of R xy with respect to H x , as shown by e and f in Figure 4 .

[0081] Thus, under a three-dimensional magnetic field, by applying a driving current with a positive and negative polarity of 2.5 mA in the x direction and a driving current with a positive and negative polarity of 2.5 mA in the y direction, through mathematical operations, such as Figure 5 as shown, the magnetic field components in the x, y, and z directions and their respective contributions to the anomalous Hall resistance can be calculated. It can be seen that the magnitudes of the magnetic fields in the three orthogonal directions are linearly related to the values of their respective contributions to the anomalous Hall resistance. Through this linear relationship, the measurement of the three-dimensional vector magnetic field can be achieved. Since a 2.5 mA pulsed current with a duration of 50 μs is used, the power consumption required for a single measurement is greatly reduced. Only 0.625 μJ is required for a single measurement.

[0082] such as Figure 6 as shown, a spectrum analyzer is used to measure the noise spectrum of the device: at a write current I = 2.5 mA, the relationship with frequency. At high frequencies, white noise (Johnson noise) dominates, while at low frequencies, 1 / f noise dominates. For a device with a width of 50 μm, at a write current of 2.5 mA, the noise value at a frequency of 1 Hz is approximately 25.9 nV / √Hz, and the corresponding magnetic noise is 2.1 nT / √Hz. This noise measurement is carried out under a constant DC current, which corresponds to the actual operating current of the device. The magnetic noise at the level of 2.1 nT at 1 Hz indicates that the magnetic field resolution of the device can reach the nanotesla level.

[0083] The heterostructure based on ferromagnetic materials, W / CoFeB / MgO / TiO of the present invention utilizes the physical property that a magnetic field in a specific direction will have a specific effect on the magnitude of the anomalous Hall resistance to prepare a sensor device at the micron size level, realizing the efficient measurement of the three-dimensional magnetic field vector. The three-dimensional magnetic field sensor has the capabilities of rapid measurement, a resolution at the nanotesla level, and ultra-low power consumption. Compared with traditional three-dimensional magnetic field vector sensors, it has a simple structure, a lower cost, is easy to miniaturize, and has a small area overhead; in practical applications, the three-dimensional magnetic field sensor proposed in this paper can be integrated on-chip at the micron or even nanoscale to achieve efficient measurement.

[0084] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the present invention and its equivalent technologies, the present invention also intends to include these modifications and variations. The above-described embodiments are only preferred embodiments given to fully illustrate the present invention, and the scope of protection is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the scope of protection of the present invention.

Claims

1. A method for detecting three-dimensional vector magnetic field based on integrated excitation and reading, characterized in that, A spin-orbit torque device sensor is adopted, and the ferromagnetic material of the spin-orbit torque device sensor has zero remanence and perpendicular magnetic anisotropy. Calibrating a three-dimensional rectangular coordinate system with two mutually perpendicular electrode directions in the plane of the spin current generating layer as the x-axis and y-axis, and the direction perpendicular to the surface of the spin current generating layer as the z-axis, includes the following steps: S1. Calibrate the sensor with a magnetic field of known magnitude and direction: Apply an excitation current to the sensor to generate a spin-polarized current in the spin current generating layer, and apply a spin-orbit torque to the zero-remanence ferromagnetic layer. Under the combined action of the spin-orbit torque, the anisotropy field, the demagnetizing field, and the applied external magnetic field of the zero-remanence ferromagnetic layer, the magnetic moment of the zero-remanence ferromagnetic layer reaches a stable state regulated by the external magnetic field. At the same time, read out the output voltage to obtain the R-H curves of the magnetic field in the x direction alone, the magnetic field in the y direction alone, and the magnetic field in the z direction alone; S2. Place the sensor in the magnetic field to be measured, apply the same positive and negative excitation currents in the x direction as in S1, and measure the output voltage in the y direction simultaneously to obtain the resistance values R1 and R2. Since the net contributions of different magnetic field components to the resistance are independent, calculate the contributions R of the magnetic field components along the x-axis and z-axis to the resistance respectively based on the resistance changes Hx and R Hz , and substitute them into the R-H curves of the magnetic fields in the corresponding directions to obtain the magnetic field components H x and H z ; S3. Keep the position of the sensor unchanged, apply the same positive and negative excitation currents in the y direction as in S1, and measure the output voltage in the x direction simultaneously to obtain two resistance values R3 and R4; calculate the contribution R of the y-axis magnetic field to the resistance based on the resistance values R3 and R4 Hy , substitute it into the R-H curve of the magnetic field in the y direction to obtain the magnetic field component H y ; S4. Calculate the magnitude and direction of the unknown magnetic field based on the three components H x 、H y 、H z measured in the x, y, and z directions of the magnetic field to be measured.

2. The method for detecting a three-dimensional vector magnetic field based on integrated excitation and reading according to claim 1, wherein In step S1, the magnitude of the excitation current is 0.1 - 2.5 mA, and the pulse width is 30 ns to 50 μs.

3. The method for detecting three-dimensional vector magnetic field based on integrated excitation and reading according to claim 1, characterized in that The spin-orbit torque device sensor includes a sensor of a cross-shaped Hall Bar structure device or a sensor of a tunnel junction device; wherein the ferromagnetic material serves as a magnetic layer in the cross-shaped Hall Bar structure device and as a free layer in the tunnel junction device.

4. The method for detecting a three-dimensional vector magnetic field based on integrated excitation and reading according to claim 3, wherein The four ends of the sensor of the cross-shaped hallbar structure device are successively the first electrode, the second electrode, the third electrode, and the fourth electrode of the device. The direction from the first electrode to the third electrode is the positive direction of the x-axis, and the direction from the fourth electrode to the second electrode is the positive direction of the y-axis; or, the direction from the second electrode to the fourth electrode is the positive direction of the x-axis, and the direction from the first electrode to the third electrode is the positive direction of the y-axis; The five ends of the sensor of the tunnel junction device structure are successively the first electrode, the second electrode, the third electrode, the fourth electrode, and the upper electrode of the device. The direction from the first electrode to the third electrode is the positive direction of the x-axis, and the direction from the fourth electrode to the second electrode is the positive direction of the y-axis.

5. The method for detecting a three-dimensional vector magnetic field based on integrated excitation and reading according to claim 4, wherein Calibrate the sensor based on the cross-shaped Hall Bar structure device: Apply an excitation current to the first electrode and the third electrode, and measure the output voltage at the second electrode and the fourth electrode simultaneously, or apply an excitation current to the second electrode and the fourth electrode, and measure the output voltage at the first electrode and the third electrode simultaneously; Calibrate the sensor based on the tunnel junction device structure: Apply an excitation current to the first electrode and the third electrode, or the second electrode or the fourth electrode, and measure the resistance between the third electrode and the upper electrode simultaneously.

6. The method for detecting a three-dimensional vector magnetic field based on integrated excitation and reading according to claim 1, wherein In step S1, while applying an excitation current to the sensor and reading out the output voltage, R-H curves of the magnetic field in the x direction alone, the magnetic field in the y direction alone, and the magnetic field in the z direction alone are obtained, which specifically include the following steps: S101. Place the sensor in a magnetic field with a magnitude change of H x and a direction in the x - direction. Apply a positive current in the x - direction and measure the output voltage in the y - direction simultaneously. Divide the voltage by the positive current to obtain the resistance R + , and obtain the R - H curve under the positive current in the x - magnetic field alone + -H x ; Apply a negative current with the same magnitude in the x - direction and measure the output voltage in the y - direction simultaneously. Divide the voltage by the negative current to obtain the resistance R - , and obtain the R - H curve under the negative current in the x - magnetic field alone - -H x ; Calculate the net contribution R of the magnetic field in the x - direction to the resistance through the R + and R - measured under the same magnitude of the magnetic field in the x - direction. R=(R + -R - ) / 2, and obtain the R - H curve under the x - magnetic field alone x ; S102. Place the sensor in a magnetic field with a magnitude of H z varying in the z - direction, apply a positive current of the same magnitude in the x - direction, and measure its voltage in the y - direction. Divide the voltage by the positive current to obtain the resistance R + , obtaining the R - H + -H z curve under a positive current in a magnetic field in the z - direction alone; apply a negative current of the same magnitude in the x - direction, measure its voltage in the y - direction, and divide the voltage by the negative current to obtain the resistance R - , obtaining the R - H z curve under a negative current in a magnetic field in the z - direction alone; through the R + and R - measured under the same magnitude of the magnetic field in the z - direction, calculate the net contribution R of the magnetic field in the x - direction to the resistance, R=(R + -R - ) / 2, obtaining the R - H z curve under a magnetic field in the z - direction alone; S103. Place the sensor in a magnetic field with a magnitude change of H y and a direction along the y-axis. Apply a positive current of the same magnitude in the y-direction, and simultaneously measure the output voltage in the x-direction. Divide the voltage by the positive current to obtain the resistance R + , and obtain the R-Hy curve under the positive current in the y magnetic field alone + . Apply a negative current of the same magnitude in the y-direction, measure its voltage in the x-direction, and divide the voltage by the negative current to obtain the resistance R - , and obtain the R-H curve under the negative current in the y magnetic field alone y . Calculate the net contribution R of the magnetic field in the y direction to the resistance through the R + and R - measured at the same magnitude of the magnetic field in the y direction. R = (R + - R - ) / 2, and obtain the R-H curve under the y magnetic field alone y .

7. The method for detecting three-dimensional vector magnetic field based on integrated excitation and reading according to claim 1, characterized in that In step S2, calculate the contributions R of the magnetic field components in the x-axis and z-axis directions to the resistance respectively based on the resistance change Hx and R Hz , and substitute them into the R-H curves of the magnetic fields in the corresponding directions to obtain the magnetic field components H x and H z , including: Based on the resistance values R1 and R2, calculate the contribution value R of the magnetic field in the z direction alone to the resistance Hz and the contribution value R of the magnetic field in the x direction alone to the resistance Hx , R Hz =(R1 + R2) / 2; R Hx =(R1 - R2) / 2; Substitute the contribution value R Hx into the R-H x curve under the separate x magnetic field to obtain the x-direction component H of the magnetic field to be measured x ; Substitute the contribution value R Hz into the R-H z curve under the separate z magnetic field to obtain the z-direction component H of the magnetic field to be measured z .

8. The method for detecting a three-dimensional vector magnetic field based on integrated excitation and reading according to claim 1, wherein In step S3, based on the resistance values R3 and R4, calculate the contribution value R of the magnetic field in the y direction alone to the resistance Hy , R Hy = (R3 - R4) / 2; Substitute the contribution value R Hy into the R-H y curve in the magnetic field in the y direction alone, and obtain the y-direction component H y of the magnetic field to be measured.

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