A method for analyzing magnetic field noise of a microscopic magnetic shielding device

Abstract

A method for analyzing the magnetic field noise of a microscopic magnetic shielding device, which includes preparing a magnetic shielding material sample, measuring the grain size and complex magnetic permeability of the magnetic shielding material, constructing a fitting model between the grain size and the complex magnetic permeability, constructing an analysis model for the magnetic field noise of the magnetic shielding device based on the grain size of the magnetic shielding material, measuring the grain size to analyze the magnetic field noise of the magnetic shielding device, without the need to measure the parameters of the formed magnetic shielding device, and can be used for the selection and design of low-noise magnetic shielding materials.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic noise measurement, in particular to a method for analyzing the magnetic field noise of a microscopic magnetic shielding device. By preparing a magnetic shielding material sample, measuring the grain size and complex magnetic permeability of the magnetic shielding material, constructing a fitting model of the grain size and the complex magnetic permeability, constructing an analysis model of the magnetic field noise of the magnetic shielding device based on the grain size of the magnetic shielding material, and measuring the grain size to analyze the magnetic field noise of the magnetic shielding device, it is not necessary to measure the parameters of the formed magnetic shielding device, and it can be used for the selection and design of low-noise magnetic shielding materials. Background Art

[0002] Quantum sensors based on the interaction between light and atoms, such as atomic magnetometers, atomic gyroscopes, and atomic clocks, are particularly sensitive to magnetic field interference. Magnetic shielding materials are materials with high magnetic permeability and low coercivity, which can effectively reduce environmental magnetic field interference and are widely used in high-precision quantum sensors. Currently, the magnetic shielding devices made of magnetic shielding materials will generate magnetization noise, which has become an important factor restricting high-precision quantum sensors. The magnetization process of magnetic shielding materials is mainly achieved through the domain wall displacement and magnetization vector rotation of internal grains. The larger the grains, the smaller the resistance when the domain wall dislocates, resulting in smaller magnetization noise. Therefore, it can be known that the magnetization noise of magnetic shielding materials can be determined by the grain size of magnetic shielding materials. Based on this, by measuring the grain size of magnetic shielding materials, the magnetic field noise of its shielding device can be directly analyzed, and it is not necessary to measure the parameters of the formed magnetic shielding device. Summary of the Invention

[0003] In view of the defects or deficiencies in the prior art, the present invention provides a method for analyzing the magnetic field noise of a microscopic magnetic shielding device. By preparing a magnetic shielding material sample, measuring the grain size and complex magnetic permeability of the magnetic shielding material, constructing a fitting model of the grain size and the complex magnetic permeability, constructing an analysis model of the magnetic field noise of the magnetic shielding device based on the grain size of the magnetic shielding material, and measuring the grain size to analyze the magnetic field noise of the magnetic shielding device, it is not necessary to measure the parameters of the formed magnetic shielding device, and it can be used for the selection and design of low-noise magnetic shielding materials.

[0004] The technical solution of the present invention is as follows:

[0005] A method for analyzing the magnetic field noise of a microscopic magnetic shielding device, characterized by comprising the following steps:

[0006] Step 1, preparing a soft magnetic material sample with a grain size of micron level for the soft magnetic material sample;

[0007] Step 2, measuring the grain size and complex magnetic permeability of the soft magnetic material;

[0008] Step 3, construct a fitting model of the grain size and the complex permeability;

[0009] Step 4, construct a magnetic field noise analysis model of the soft magnetic shielding device based on the grain size of the soft magnetic material;

[0010] Step 5, according to the magnetic field noise analysis model of the soft magnetic shielding device, analyze the magnetic field noise of the soft magnetic shielding device by measuring the grain size.

[0011] The soft magnetic material in the step 1 includes the following substances with high magnetic permeability and low coercivity: ferrite or nickel-iron alloy or iron-silicon alloy.

[0012] The soft magnetic shielding device in the step 4 is spherical shell-shaped or rectangular barrel-shaped or cylindrical barrel-shaped.

[0013] The fitting model in the step 3 adopts the following linear relation: μ eff = a + b·D, where μ eff is the effective complex permeability, a and b are fitting parameters, and D is the grain size of the soft magnetic material.

[0014] The magnetic field noise analysis model of the soft magnetic shielding device in the step 4 includes adopting the following functional relation:

[0015]

[0016] where δB magnb represents the magnetic field noise of the spherical shell-shaped magnetic shielding device, μ 0 is the vacuum permeability, k B is the Boltzmann constant, T is the temperature, r is the sphere radius, t is the sphere shell thickness, f is the frequency, δ loss is the magnetic loss angle, a and b are fitting parameters, and D is the grain size of the soft magnetic material.

[0017] The magnetic field noise analysis model of the soft magnetic shielding device in the step 4 includes adopting the following functional relation:

[0018]

[0019] where δB magnr represents the magnetic field noise of the rectangular barrel-shaped magnetic shielding device, μ 0 is the vacuum permeability, k B is the Boltzmann constant, T is the temperature, r is the center distance, t is the barrel wall thickness, f is the frequency, δ loss is the magnetic loss angle, a and b are fitting parameters, and D is the grain size of the soft magnetic material.

[0020] The magnetic field noise analysis model of the soft magnetic shielding device in the step 4 includes adopting the following functional relation:

[0021]

[0022] where δB magnc represents the magnetic field noise of the cylindrical barrel-shaped magnetic shielding device, μ 0 is the vacuum permeability, k B is the Boltzmann constant, T is the temperature, r is the central distance, t is the barrel wall thickness, f is the frequency, δ loss is the magnetic loss angle, a and b are fitting parameters, D is the grain size of the soft magnetic material, and G is the cylindrical barrel shape factor.

[0023] The technical effects of the present invention are as follows: A microscopic magnetic shielding device magnetic field noise analysis method of the present invention, compared with the existing solutions, the main advantage is that the existing magnetic shielding device magnetic field noise analysis method requires parameter measurement of the formed shielding device. The present invention designs a microscopic magnetic shielding device magnetic field noise analysis method, and can analyze the magnetic field noise of the magnetic shielding device through the grain size, which helps in the selection and design of low-noise magnetic shielding materials. Brief Description of the Drawings

[0024] Figure 1 is a schematic flow chart of implementing a microscopic magnetic shielding device magnetic field noise analysis method of the present invention. Figure 1 It includes Step 1, preparing a soft magnetic material sample; Step 2, measuring the grain size (i.e., the grain size) and the complex magnetic permeability of the soft magnetic material; Step 3, constructing a fitting model between the grain size and the complex magnetic permeability; Step 4, constructing a soft magnetic shielding device magnetic field noise analysis model based on the grain size of the soft magnetic material; Step 5, measuring the grain size to analyze the magnetic field noise of the soft magnetic shielding device. Detailed Embodiments

[0025] The following combines the drawings ( Figure 1 ) and embodiments to describe the present invention.

[0026] Figure 1 is a schematic flow chart of implementing a microscopic magnetic shielding device magnetic field noise analysis method of the present invention. Referring to Figure 1 as shown, a microscopic magnetic shielding device magnetic field noise analysis method is characterized by including the following steps: Step 1, preparing a soft magnetic material sample, where the grain size of the soft magnetic material sample is in the micron level; Step 2, measuring the grain size and the complex magnetic permeability of the soft magnetic material; Step 3, constructing a fitting model between the grain size and the complex magnetic permeability; Step 4, constructing a soft magnetic shielding device magnetic field noise analysis model based on the grain size of the soft magnetic material; Step 5, according to the soft magnetic shielding device magnetic field noise analysis model, analyzing the magnetic field noise of the soft magnetic shielding device by measuring the grain size.

[0027] The soft magnetic material in the step 1 includes the following substances with high magnetic permeability and low coercivity: ferrite or nickel-iron alloy or iron-silicon alloy. The soft magnetic shielding device in the step 4 is spherical shell-shaped or rectangular barrel-shaped or cylindrical barrel-shaped. The fitting model in the step 3 adopts the following linear relation: μ eff = a + b·D, where μ eff is the effective complex magnetic permeability, a and b are fitting parameters, and D is the grain size of the soft magnetic material.

[0028] The magnetic field noise analysis model of the soft magnetic shielding device in the step 4 includes adopting the following functional relation:

[0029]

[0030] where δB magnb represents the magnetic field noise of the spherical shell-shaped magnetic shielding device, μ 0 is the vacuum magnetic permeability, k B is the Boltzmann constant, T is the temperature, r is the sphere radius, t is the sphere shell thickness, f is the frequency, δ loss is the magnetic loss angle, a and b are fitting parameters, and D is the grain size of the soft magnetic material.

[0031] The magnetic field noise analysis model of the soft magnetic shielding device in the step 4 includes adopting the following functional relation:

[0032]

[0033] where δB magnr represents the magnetic field noise of the rectangular barrel-shaped magnetic shielding device, μ 0 is the vacuum magnetic permeability, k B is the Boltzmann constant, T is the temperature, r is the center distance, t is the barrel wall thickness, f is the frequency, δ loss is the magnetic loss angle, a and b are fitting parameters, and D is the grain size of the soft magnetic material.

[0034] The magnetic field noise analysis model of the soft magnetic shielding device in the step 4 includes adopting the following functional relation:

[0035]

[0036] where δB magnc represents the magnetic field noise of the cylindrical barrel-shaped magnetic shielding device, μ 0 is the vacuum magnetic permeability, k B is the Boltzmann constant, T is the temperature, r is the center distance, t is the barrel wall thickness, f is the frequency, δ loss is the magnetic loss angle, a and b are fitting parameters, D is the grain size of the soft magnetic material, and G is the cylindrical barrel shape factor.

[0037] The object of the present invention is to provide a method for analyzing the magnetic field noise of a microscopic magnetic shielding device, which analyzes the magnetic field noise of the magnetic shielding device by measuring the grain size of the magnetic shielding material, without the need to measure the parameters of the formed magnetic shielding device, and can be used for the selection and design of low-noise magnetic shielding materials. To solve the above technical problems, a method for analyzing the magnetic field noise of a microscopic magnetic shielding device of the present invention includes:

[0038] Preparing a magnetic shielding material sample;

[0039] Measuring the grain size and complex magnetic permeability of the magnetic shielding material;

[0040] Constructing a fitting model between the grain size and the complex magnetic permeability;

[0041] Constructing a magnetic field noise analysis model of the magnetic shielding device based on the grain size of the magnetic shielding material;

[0042] Measuring the grain size to analyze the magnetic field noise of the magnetic shielding device.

[0043] Preferably, the magnetic shielding material has high magnetic permeability and low coercivity, including but not limited to ferrites, nickel-iron alloys, and iron-silicon alloys, etc.

[0044] Preferably, the shape of the magnetic shielding device can be spherical, rectangular, and cylindrical.

[0045] Preferably, the fitting model shows that the grain size and the complex magnetic permeability have a linear relationship.

[0046] Preferably, the linear relationship can be expressed as:

[0047] μ eff = a + b·D

[0048] where μ eff is the effective complex magnetic permeability, a and b are fitting parameters, and D is the grain size of the magnetic shielding material.

[0049] Preferably, the relationship between the magnetic field noise of the spherical magnetic shielding device and the grain size of the magnetic shielding material is as follows:

[0050]

[0051] where μ 0 is the magnetic permeability of vacuum, k B is the Boltzmann constant, T is the temperature, r is the sphere radius, t is the thickness, f is the frequency, tan(δ loss ) is the tangent of the magnetic loss angle, μ eff is the effective complex magnetic permeability, a and b are fitting parameters, and D is the grain size of the magnetic shielding material.

[0052] Preferably, the relationship between the magnetic field noise of the square magnetic shielding device and the grain size of the magnetic shielding material is as follows:

[0053]

[0054] where μ 0 is the magnetic permeability of vacuum, k B is the Boltzmann constant, T is the temperature, r is the central distance, t is the thickness, f is the frequency, tan(δ loss ) is the tangent of the magnetic loss angle, μ eff is the effective complex magnetic permeability, a and b are fitting parameters, and D is the grain size of the magnetic shielding material.

[0055] Preferably, the relationship between the magnetic field noise of the cylindrical magnetic shielding device and the grain size of the magnetic shielding material is as follows:

[0056]

[0057] where μ 0 is the magnetic permeability of vacuum, k B is the Boltzmann constant, T is the temperature, r is the central distance, t is the thickness, f is the frequency, tan(δ loss ) is the tangent of the magnetic loss angle, μ eff is the effective complex magnetic permeability, a and b are fitting parameters, D is the grain size of the magnetic shielding material, and G is the shape factor.

[0058] The content not described in detail in the specification of the present invention belongs to the prior art well-known to those skilled in the art. It is hereby specified that the above description helps those skilled in the art to understand the present invention, but does not limit the protection scope of the present invention. Any implementation that makes equivalent substitutions, modifications, improvements, and / or simplifies the above description without departing from the essence of the present invention falls within the protection scope of the present invention.

Claims

1. A method for analyzing the magnetic field noise of a microscopic magnetic shielding device, characterized in that, it comprises the following steps: Step 1, prepare a soft magnetic material sample, and the grain size of the soft magnetic material sample is in the micron range; Step 2, measure the grain size and complex magnetic permeability of the soft magnetic material; Step 3, construct a fitting model of the grain size and the complex magnetic permeability; Step 4, construct an analysis model for the magnetic field noise of the soft magnetic shielding device based on the grain size of the soft magnetic material; Step 5, according to the analysis model for the magnetic field noise of the soft magnetic shielding device, analyze the magnetic field noise of the soft magnetic shielding device by measuring the grain size.

2. The method for analyzing the magnetic field noise of a microscopic magnetic shielding device according to claim 1, characterized in that, the soft magnetic material in Step 1 includes the following substances with high magnetic permeability and low coercivity: ferrite or nickel-iron alloy or iron-silicon alloy.

3. The method for analyzing the magnetic field noise of a microscopic magnetic shielding device according to claim 1, characterized in that, the soft magnetic shielding device in Step 4 is spherical shell-shaped or rectangular barrel-shaped or cylindrical barrel-shaped.

4. The method for analyzing the magnetic field noise of a microscopic magnetic shielding device according to claim 1, characterized in that, In the step 3, the fitting model adopts the following linear relationship: μ eff = a + b·D, where μ eff is the effective complex magnetic permeability, a and b are fitting parameters, and D is the grain size of the soft magnetic material.

5. The method for analyzing the magnetic field noise of a microscopic magnetic shielding device according to claim 1, characterized in that, the analysis model for the magnetic field noise of the soft magnetic shielding device in Step 4 includes the use of the following functional relationship: where δB magnb represents the magnetic field noise of the spherical shell-shaped magnetic shielding device, μ 0 is the vacuum permeability, k B is the Boltzmann constant, T is the temperature, r is the sphere radius, t is the spherical shell thickness, f is the frequency, δ loss is the magnetic loss angle, a and b are fitting parameters, and D is the grain size of the soft magnetic material.

6. The method for analyzing the magnetic field noise of a microscopic magnetic shielding device according to claim 1, characterized in that, the analysis model for the magnetic field noise of the soft magnetic shielding device in Step 4 includes the use of the following functional relationship: where δB magnr represents the magnetic field noise of the rectangular barrel-shaped magnetic shielding device, μ 0 is the vacuum permeability, k B is the Boltzmann constant, T is the temperature, r is the central distance, t is the barrel wall thickness, f is the frequency, δ loss is the magnetic loss angle, a and b are fitting parameters, and D is the grain size of the soft magnetic material.

7. The method for analyzing the magnetic field noise of a microscopic magnetic shielding device according to claim 1, characterized in that, the analysis model for the magnetic field noise of the soft magnetic shielding device in Step 4 includes the use of the following functional relationship: where δB magnc represents the magnetic field noise of the cylindrical barrel-shaped magnetic shielding device, μ 0 is the magnetic permeability of vacuum, k B is the Boltzmann constant, T is the temperature, r is the central distance, t is the barrel wall thickness, f is the frequency, δ loss is the magnetic loss angle, a and b are fitting parameters, D is the grain size of the soft magnetic material, and G is the cylindrical barrel shape factor.

Images