Micro-magnetic pole probe and preparation method and application thereof

Abstract

The invention discloses a micro magnetic pole probe as well as a preparation method and application thereof, and belongs to the technical field of scanning probe coatings of core sensors of scanning ion conductance microscopes. According to the preparation method disclosed by the invention, when the ferroferric oxide is prepared by adopting a chemical coprecipitation method and the magnetic substance is prepared by adopting the chemical coprecipitation method, the reaction is simultaneously carried out in the whole reaction system, the adhesion uniformity of the ferroferric oxide in the probe is ensured, and compared with the prior art, the preparation method disclosed by the invention is simple to operate and high in repeatability; wide application prospects are realized. When the device is applied to the scanning ion conductance microscope, the magnetic field intensity can be used as a feedback signal of motion, the distance of magnetic ferroferric oxide attached to the probe is detected through the magnitude of the output current of the TMR sensor, and the feedback range of the motion of the probe of the scanning ion conductance microscope in the Z-axis direction is enlarged, so that the downward probing speed of the probe is increased; the scanning speed is improved, and the impact force is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of scanning probe coatings for a core sensor of a scanning ion conductivity microscope, and in particular relates to a micro-magnetic pole probe and a preparation method and application thereof. Background Art

[0002] The level of microscopy technology determines the research boundaries of human science and technology at the spatial scale. It is the basis and necessary tool for the development of cutting-edge fields such as life sciences and electrochemistry. Scanning ion conductivity microscopy (SICM) is a new type of scanning probe microscope developed on the basis of scanning tunneling microscopy and atomic force microscopy. As a new member of the scanning probe microscope family, SICM is widely used in nanoscale biological imaging. Scanning ion conductivity microscopy is a non-contact scanning probe microscope that can perform non-destructive, non-contact, nanoscale resolution imaging of the three-dimensional morphology of the surface of the sample under liquid physiological conditions. In addition, SICM has no requirements for the conductivity of the sample under test, and does not require complex pretreatment such as dehydration, curing, and metal spraying. Therefore, SICM has been widely used in medicine, biology, electrochemistry and other fields in recent years. The current scanning ion conductivity probe microscopy imaging method is difficult to meet the application requirements in terms of dynamic and high-speed capture of key information. At present, most scanning ion conductivity detection technologies use a jump mode, that is, the probe moves from the Z-axis starting position to the vicinity of the sample surface, records the probe position and ion current (or redox current) information at this time, then withdraws to the Z-axis starting position and moves horizontally to the next point, performs a probe detection at the next point, and repeats this process until all preset points are scanned. The jump mode can effectively avoid collisions between the probe and the sample when scanning complex samples, but at the same time, since multiple Z-axis probes are required, the movement of the probe has many "redundant paths", which greatly increases the total time required for scanning detection. Over the years, people have made a lot of efforts to improve the speed of scanning ion conductivity detection technology. At present, the research on improving the scanning speed is mainly divided into two categories: "trajectory planning" and "increasing the approach speed". The trajectory planning method is essentially to shorten the scanning path, that is, to reduce the number of scanning pixels and shorten the approach path, such as pre-scanning method and under-sampling method. Such methods usually require prior knowledge of the scanning terrain through pre-scanning or other methods, so it is difficult to adapt to complex scanning targets with unknown morphology. The methods to improve the approach speed mainly include two categories: approach control algorithm improvement and hardware improvement, such as hybrid scanning method, dual piezoelectric ceramic method, design of high-frequency piezoelectric ceramic drive mechanism, overshoot compensation method, speed control algorithm, etc.

[0003] Although the above-mentioned speed-up methods can improve the scanning speed to a certain extent, it is known from the analysis of the detection principle of scanning ion conductivity detection technology that when the distance between the probe and the sample is less than the diameter of the pipette tip opening (generally a few nanometers to a few hundred nanometers), the ion current in the circuit will change, and the control algorithm can feedback the probe's approach action to slow the probe down to a standstill. Since the scanning probe drive and load are a large inertial system, the braking of the scanning mechanism from high-speed movement to stillness within a very small distance usually adds a large inertial force, which causes micro-deformation of the drive structure, resulting in overshoot and collision of the probe, or even breakage. Summary of the invention

[0004] The object of the present invention is to provide a micro-magnetic pole probe and a preparation method and application thereof, so as to solve the technical problems of low scanning rate and large inertial force caused by too small feedback interval when using existing probes.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The invention discloses a method for preparing a micro magnetic pole probe, comprising the following steps: The iron salt solution is poured into the interior of the scanning probe, and then a heating treatment, a heat drawing treatment and a magnetization treatment are performed in sequence to obtain a micro-magnetic pole probe; The iron salt solution is soluble Fe 3+ Metal salt solutions and soluble Fe 2+ A mixture of ionic metal salt solutions.

[0006] Furthermore, the Fe in the iron salt solution 3+ and Fe 2+ The molar ratio is 2: (1~1.2); The pH value of the iron salt solution is adjusted to 5-6 by adding an alkaline solution; the alkaline solution is one of a sodium hydroxide solution, a sodium carbonate solution and ammonia water.

[0007] Furthermore, the soluble Fe 3+ The metal salt solution is soluble Fe 3+ The metal salt and deionized water are mixed to obtain the soluble Fe 3+ Metal salt is Fe 3+ Any of the sulfate and chloride salts of ions; The soluble Fe 2+ Ionic metal salt solution is soluble Fe 2+ Ionic metal salt and deionized water are mixed to obtain; the soluble Fe 2+ Ionic metal salt is Fe 2+ Any one of the sulfate and chloride solutions.

[0008] Furthermore, when the iron salt solution is poured into the scanning probe, the scanning probe is placed at an angle of 50 to 70 degrees to the vertical direction; and a syringe is used to pour the iron salt solution to 1 / 3 to 1 / 2 of the scanning probe.

[0009] Furthermore, the process parameters of the heating treatment are: heating at 40-50° C. for 50-70 min in an inert atmosphere; The heat drawing process is performed by using a drawing device, and the drawing device is a micro-motor drawing instrument; The laser output power of the micro-motor drawing instrument is 200-250, the laser scanning speed is 4, the heating stop speed is 50-80, the multi-step drawing delay is 200~250, and the pulling force is 125~150; The magnetization treatment time is 10 to 15 seconds.

[0010] The invention also discloses a micro-magnetic pole probe prepared by the preparation method; the opening radius of the micro-magnetic pole probe is 10 nanometers to 200 nanometers.

[0011] The present invention also discloses the application of the micro-magnetic pole probe in a scanning ion conductivity microscope, which comprises the following steps: The micro-magnetic pole probe is mounted on the Z-direction piezoelectric ceramic, the probe electrode of the ion current circuit is arranged in the current channel of the micro-magnetic pole probe, and an ion solution is added into the current channel, and the sample electrode is arranged at a position opposite to the probe electrode of the inner ion current circuit of the micro-magnetic pole probe; the TMR sensor is arranged under the culture dish; Move the micro-magnetic pole probe downward along the Z-axis direction at a relatively fast speed to a preset distance from the sample surface for rough positioning, thereby completing the rough positioning movement of the micro-magnetic pole probe; The micro-magnetic pole probe continues to move downward along the Z-axis direction, and moves at a relatively slow speed to a precisely positioned preset distance from the sample surface, completing the precise positioning movement of the micro-magnetic pole probe; The information data of the micro-magnetic pole probe at this time is recorded, and the three-dimensional morphology and electrochemical information of the sample are obtained according to the information data processing.

[0012] Furthermore, the initial position of the micro-pole probe installed on the Z-direction piezoelectric ceramic is determined by the ion current variation curve combined with the prior knowledge of the sample fluctuation height; The feedback signal of the coarse positioning movement of the micro-magnetic pole probe is the current output by the TMR sensor; the feedback signal of the precise positioning movement of the micro-magnetic pole probe is the ion current of the ion circuit.

[0013] Furthermore, the coarse positioning preset distance is 5-10 times the opening radius of the micro-magnetic pole probe; and the precise positioning preset distance is the opening radius of the micro-magnetic pole probe.

[0014] Furthermore, the faster speed is 10 μm / ms to 160 μm / ms, and the slower speed is 0.1 nm / ms to 50 nm / ms; the information data includes position information, ion current information and redox current information of the micro-magnetic pole probe.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a preparation method of a micro-magnetic pole probe. The chemical coprecipitation method is used to prepare ferroferric oxide. When the magnetic material is prepared by the chemical coprecipitation method, the reaction is carried out simultaneously in the entire reaction system, thereby ensuring the uniformity of the attachment of ferroferric oxide in the probe. Compared with the prior art, the preparation method is simple to operate, highly repeatable, and has broad application prospects.

[0016] The present invention also discloses the application of the micro-magnetic pole probe in a scanning ion conductivity microscope. Since the magnetic field strength of a magnetic substance will change greatly at a distance of 1 to 2 microns from the magnetic substance, the magnetic field strength can be used as a feedback signal of the movement. The distance of the magnetic ferroferric oxide to which the probe is attached is detected by the magnitude of the output current of a TMR sensor, thereby increasing the feedback range of the scanning ion conductivity microscope probe in the Z-axis direction, thereby increasing the downward speed of the probe, improving the scanning speed, and reducing the impact force. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the system structure when the micro-magnetic pole probe used for scanning ion conductivity microscopy in the present invention is used; Wherein: 1-outer wall; 2-magnetic material; 3-probe electrode; 4-sample electrode; 5-TMR sensor; 6-sample. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0019] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0020] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0021] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0022] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0023] The present invention provides a method for preparing a micro-magnetic pole probe, comprising the following steps: Step 1: First, accurately weigh the soluble Fe according to the stoichiometric ratio. 3+ Ionic metal salts, soluble Fe 2+ Ionic metal salts, the molar ratio is 2:1, then dissolved in deionized water, mixed well and added with alkaline solution, and the pH value of the iron salt solution is adjusted to 5-6; Step 2: Use a clamping device to place the scanning probe at an angle of 60° to the vertical direction, and use a syringe to inject the iron salt solution into the inner half of the scanning probe; Step 3: Place the scanning probe in a heating furnace protected by inert gas at a temperature of 50°C for 1 hour, and ferroferric oxide is deposited on the inner surface of the probe; Step 4: Place the probe embryo on a hot drawing device, set the drawing parameters to laser output power 200-250, laser scanning speed 4, stop heating speed 50-80, multi-step drawing delay 250, and pulling force 150, and then draw it into a finished micro-pole probe of a specified shape; Step 5: Magnetize the successfully prepared micro-pole scanning probe using a magnetizer, and then use a USB three-axis magnetometer to detect the magnetic field strength of the micro-pole scanning probe.

[0024] Preferably, in step 1, soluble Fe 3+ Ionic metal salt is Fe 3+ Any of the sulfate and chloride solutions of ions, soluble Fe 2+ Ionic metal salt is Fe 2+ Any of the sulfate and chloride solutions of ions.

[0025] Preferably, in step 1, the alkaline solution is one of sodium hydroxide solution, sodium carbonate solution and ammonia water.

[0026] Preferably, in step 2, the syringe is a 1 mL medical syringe, and the needle specification is 0.45*16RWLB.

[0027] Preferably, in step 2, the perfusion process is to perfuse the iron salt solution into 1 / 2 of the probe.

[0028] Preferably, in step 3, the inert gas is nitrogen, argon or helium.

[0029] Preferably, in step 4, the hot drawing device is a P-2000 micromotor drawing instrument, and the drawing parameters are laser output power 200-250, laser scanning speed 4, stop heating speed 50-80, multi-step drawing delay 250, and pulling force 150.

[0030] Preferably, in step 4, the opening radius of the drawn micro-magnetic pole probe is 10 nanometers to 500 nanometers.

[0031] Preferably, in step 5, the magnetization time is 10 s.

[0032] Preferably, in step 5, the magnetic field strength detected is the magnetic field strength of 0.5 mm at the tip of the micro-magnetic pole probe.

[0033] The invention also discloses a micro-magnetic pole probe prepared by the preparation method.

[0034] like Figure 1 As shown, the present invention also discloses a method for using the micro-magnetic pole probe for a scanning ion conductivity microscope, including: The micro-pole probe is mounted on the Z-direction piezoelectric ceramic, and the micro-pole probe includes an outer wall 1 and a current channel inside the outer wall, and a magnetic material 2 is attached to the inner surface of the outer wall; The probe electrode 3 of the ion current circuit is set in the current channel, and the ion solution is added into the current channel. The sample electrode 4 is set at a position opposite to the electrode inside the micro-magnetic pole probe; the TMR sensor 5 is set under the culture dish; Coarse positioning movement: the micro-magnetic pole probe moves downward along the Z-axis direction and moves at a relatively fast speed to a preset distance for coarse positioning from the surface of the sample 6, completing the coarse positioning movement of the micro-magnetic pole probe; Precise positioning movement: After the rough positioning movement is completed, the micro-magnetic pole probe continues to move downward along the Z-axis direction, and moves at a slower speed to a preset distance from the surface of the sample 6 for precise positioning, completing the precise positioning movement of the micro-magnetic pole probe; Recording information: After the precise positioning and movement is completed, the position information, ion current information and redox current information of the micro-magnetic pole probe are recorded; Scanning point movement: the micro-pole probe moves to the next scanning point; Repeat the four steps of coarse positioning movement, precise positioning movement, information recording, and scanning point movement to complete the information recording of all scanning points, and process the data according to the recorded information to obtain the three-dimensional morphology and electrochemical information of sample 6.

[0035] In some specific embodiments, the initial position of the micro-pole probe in the Z direction is determined by combining the ion current variation curve with the prior knowledge of the sample fluctuation height.

[0036] In some specific embodiments, the feedback signal of the coarse positioning movement is the current output by the TMR sensor, and the feedback signal of the fine positioning movement is the ion current of the ion circuit.

[0037] In some specific embodiments, the coarse positioning preset distance is 5-10 times the opening radius of the micro-magnetic pole, and the precise positioning preset distance is the opening radius of the micro-magnetic pole probe.

[0038] In some specific embodiments, the faster speed is 10 μm / ms-160 μm / ms, and the slower speed is 0.1 nm / ms-50 nm / ms.

[0039] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0040] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0041] Example 1 A method for preparing a micro-magnetic pole probe comprises the following steps: First, FeCl2, FeCl3, Fe 2+ and Fe 3+ The molar ratio of ferric salt is 1:2, and then it is dissolved in deionized water, mixed evenly, and NaOH solution is added to adjust the pH value of the iron salt solution to 5-6; Use a clamping device to place the probe embryo at an angle of 60° to the vertical direction, and use a syringe to inject the iron salt solution into the inner half of the scanning probe embryo; The scanning probe was placed in a heating furnace protected by inert gas, the heating temperature was 50°C, the duration was 1 hour, and ferroferric oxide was deposited on the inner surface of the probe; The probe embryo is placed on a hot-pulling device, with a laser output power of 250W, a laser scanning speed of 4 mm / min, a stop heating speed of 50 mm / min, a multi-step pulling delay of 250s, and a pulling force of 150N, and then pulled into a finished probe of a specified shape; The successfully prepared finished probe was magnetized using a magnetizer, and then the magnetic field strength of the finished probe was tested using a USB three-axis magnetometer. Finally, a micro-magnetic pole probe with uniformly attached magnetic ferroferric oxide was obtained, and the probe opening radius was 10 nm.

[0042] Example 2 A method for preparing a micro-magnetic pole probe comprises the following steps: First, FeCl2, FeCl3, Fe 2+ and Fe 3+ The molar ratio is 1:2, then it is dissolved in deionized water, mixed evenly, and NaCO3 solution is added to adjust the pH value of the iron salt solution to 5-6; Use a clamping device to place the probe embryo at an angle of 60° to the vertical direction, and use a syringe to inject the iron salt solution into the inner half of the scanning probe embryo; The scanning probe was placed in a heating furnace protected by inert gas, the heating temperature was 50°C, the duration was 1 hour, and ferroferric oxide was deposited on the inner surface of the probe; The probe embryo was placed on a hot-pulling device, with a laser output power of 200 W, a laser scanning speed of 4 mm / min, a stop heating speed of 80 mm / min, a multi-step pulling delay of 250 s, and a pulling force of 150 N, and then pulled into a finished probe of a specified shape; The successfully prepared finished probe was magnetized using a magnetizer, and then the magnetic field strength of the finished probe was tested using a USB three-axis magnetometer. Finally, a micro-magnetic pole probe with uniformly attached magnetic ferroferric oxide was obtained, and the probe opening radius was 200nm.

[0043] Example 3 A method for preparing a micro-magnetic pole probe comprises the following steps: First, FeCl2, FeCl3, Fe 2+ and Fe 3+ The molar ratio of iron salt is 1.2:2, and then it is dissolved in deionized water, mixed evenly, and then NaCO3 solution is added to adjust the pH value of the iron salt solution to 5-6; Use a clamping device to place the probe embryo at an angle of 70° to the vertical direction, and use a syringe to inject the iron salt solution into the inner 1 / 3 position of the scanning probe embryo; The scanning probe was placed in a heating furnace protected by inert gas, the heating temperature was 40°C, the duration was 70 minutes, and ferroferric oxide was deposited on the inner surface of the probe; The probe embryo was placed on a hot-pulling device, with a laser output power of 250 W, a laser scanning speed of 4 mm / min, a stop heating speed of 50 mm / min, a multi-step pulling delay of 200 s, and a pulling force of 120 N, and then pulled into a finished probe of a specified shape; The successfully prepared finished probe was magnetized for 15 seconds using a magnetizer, and then the magnetic field strength of the finished probe was tested using a USB three-axis magnetometer, and finally a micro-magnetic pole probe with magnetic ferroferric oxide uniformly attached was obtained.

[0044] Application Example 1 The micro-magnetic pole probe prepared in Example 1 is installed on the Z-direction piezoelectric ceramic, the micro-magnetic pole probe comprises an outer wall 1 and a current channel inside the outer wall, and the magnetic material 2 is attached to the inner surface of the outer wall; The probe electrode 3 of the ion current circuit is set in the current channel, and the ion solution is added into the current channel. The sample electrode 4 is set at a position opposite to the electrode inside the micro-magnetic pole probe; the TMR sensor 5 is set under the culture dish; Coarse positioning movement: the micro-magnetic pole probe moves downward along the Z-axis direction, with the current output by the TMR sensor 5 as the feedback signal, and moves to a position 100 nm away from the surface of the sample 6 at a speed of 10 μm / ms, completing the coarse positioning movement of the micro-magnetic pole probe; Precise positioning movement: After the rough positioning movement is completed, the micro-magnetic pole probe continues to move downward along the Z-axis direction with the ion current of the ion circuit as the feedback signal, and moves to a distance of 10nm from the surface of the sample 6 at a speed of 0.1nm / ms, completing the precise positioning movement of the micro-magnetic pole probe; Recording information: After the precise positioning and movement is completed, the position information, ion current information and redox current information of the micro-magnetic pole probe are recorded; Scanning point movement: the micro-pole probe moves to the next scanning point; The four steps of coarse positioning movement, precise positioning movement, information recording, and scanning point movement are repeated to complete the information recording of all scanning points. The three-dimensional morphology and electrochemical information of sample 6 are obtained based on the recorded information processing data.

[0045] Application Example 2 The micro-magnetic pole probe prepared in Example 2 is installed on the Z-direction piezoelectric ceramic, the micro-magnetic pole probe comprises an outer wall 1 and a current channel inside the outer wall, and the magnetic material 2 is attached to the inner surface of the outer wall; The probe electrode 3 of the ion current circuit is set in the current channel, and the ion solution is added into the current channel. The sample electrode 4 is set at a position opposite to the electrode inside the micro-magnetic pole probe; the TMR sensor 5 is set under the culture dish; Coarse positioning movement: the micro-magnetic pole probe moves downward along the Z-axis direction, using the current output by the TMR sensor 5 as a feedback signal, and moves at a speed of 160 μm / ms to a distance of 1000 nm from the surface of the sample 6, completing the coarse positioning movement of the micro-magnetic pole probe; Precise positioning movement: After the rough positioning movement is completed, the micro-magnetic pole probe continues to move downward along the Z-axis direction with the ion current of the ion circuit as the feedback signal, and moves to a distance of 200nm from the surface of the sample 6 at a speed of 50nm / ms, completing the precise positioning movement of the micro-magnetic pole probe; Recording information: After the precise positioning and movement is completed, the position information, ion current information and redox current information of the micro-magnetic pole probe are recorded; Scanning point movement: the micro-pole probe moves to the next scanning point; Repeat the four steps of coarse positioning movement, precise positioning movement, information recording, and scanning point movement to complete the information recording of all scanning points. According to the recorded information processing data, a three-dimensional morphology image and electrochemical information of sample 6 similar to that of Example 1 are obtained. The image resolution is lower, but the scanning speed is faster.

[0046] The present invention deposits magnetic ferroferric oxide on the inner surface of a scanning probe to produce a micro-magnetic pole probe with a magnetic tip; the micro-magnetic pole probe produced by adopting the technical solution has low cost, simple process and good repeatability, and the feedback range of a scanning ion conductivity microscope can be increased by using the micro-magnetic pole probe, thereby improving its scanning rate.

[0047] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a micro-magnetic pole probe, characterized in that: The following steps are involved: The iron salt solution is poured into the interior of the scanning probe, and then a heating treatment, a heat drawing treatment and a magnetization treatment are performed in sequence to obtain a micro-magnetic pole probe; The iron salt solution is soluble Fe 3+ Metal salt solutions and soluble Fe 2+ A mixture of ionic metal salt solutions.

2. The method for preparing a micro-magnetic pole probe according to claim 1, characterized in that: The Fe in the iron salt solution 3+ and Fe 2+ The molar ratio is 2: (1~1.2); The pH value of the iron salt solution is adjusted to 5-6 by adding an alkaline solution; the alkaline solution is one of a sodium hydroxide solution, a sodium carbonate solution and ammonia water.

3. The method for preparing a micro-magnetic pole probe according to claim 1, characterized in that: The soluble Fe 3+ The metal salt solution is soluble Fe 3+ The metal salt and deionized water are mixed to obtain the soluble Fe 3+ Metal salt is Fe 3+ Any of the sulfate and chloride salts of ions; The soluble Fe 2+ Ionic metal salt solution is soluble Fe 2+ Ionic metal salt and deionized water are mixed to obtain; the soluble Fe 2+ Ionic metal salt is Fe 2+ Any one of the sulfate and chloride solutions.

4. The method for preparing a micro-magnetic pole probe according to claim 1, characterized in that: When the iron salt solution is poured into the scanning probe, the scanning probe is placed at an angle of 50 to 70 degrees to the vertical direction; the iron salt solution is poured into the scanning probe to 1 / 3 to 1 / 2 by using a syringe.

5. The method for preparing a micro-magnetic pole probe according to claim 1, characterized in that: The process parameters of the heating treatment are: heating at 40-50°C for 50-70 minutes in an inert atmosphere; The heat drawing process is performed by using a drawing device, and the drawing device is a micro-motor drawing instrument; The laser output power of the micro-motor drawing instrument is 200-250, the laser scanning speed is 4, the heating stop speed is 50-80, the multi-step drawing delay is 200~250, and the pulling force is 125~150; The magnetization treatment time is 10 to 15 seconds.

6. A micro-magnetic pole probe, characterized in that: Prepared by the preparation method described in any one of claims 1 to 5; The opening radius of the micro-magnetic pole probe is 10 nanometers to 200 nanometers.

7. Use of a micro-magnetic pole probe according to claim 6 in a scanning ion conductivity microscope, characterized in that: The following steps are involved: The micro-pole probe is mounted on the Z-direction piezoelectric ceramic, the probe electrode of the ion current circuit is arranged in the current channel of the micro-pole probe, an ion solution is added into the current channel, and the sample electrode is arranged at a position opposite to the probe electrode of the inner ion current circuit of the micro-pole probe; Place the TMR sensor below the culture dish; Move the micro-magnetic pole probe downward along the Z-axis direction at a relatively fast speed to a preset distance from the sample surface for rough positioning, thereby completing the rough positioning movement of the micro-magnetic pole probe; The micro-magnetic pole probe continues to move downward along the Z-axis direction, and moves at a relatively slow speed to a precisely positioned preset distance from the sample surface, completing the precise positioning movement of the micro-magnetic pole probe; The information data of the micro-magnetic pole probe at this time is recorded, and the three-dimensional morphology and electrochemical information of the sample are obtained according to the information data processing.

8. The use of a micro-magnetic pole probe in a scanning ion conductivity microscope according to claim 7, characterized in that: The initial position of the micro-pole probe installed on the Z-axis piezoelectric ceramic is determined by the ion current variation curve combined with the prior knowledge of the sample fluctuation height; The feedback signal of the coarse positioning movement of the micro-magnetic pole probe is the current output by the TMR sensor; The feedback signal of the precise positioning movement of the micro-magnetic pole probe is the ion current of the ion circuit.

9. The use of a micro-magnetic pole probe in a scanning ion conductivity microscope according to claim 7, characterized in that: The preset distance for rough positioning is 5-10 times the opening radius of the micro-magnetic pole probe; the preset distance for precise positioning is the opening radius of the micro-magnetic pole probe.

10. The use of a micro-magnetic pole probe in a scanning ion conductivity microscope according to claim 7, characterized in that: The faster speed is 10 μm / ms to 160 μm / ms, and the slower speed is 0.1 nm / ms to 50 nm / ms; the information data includes the position information, ion current information and oxidation-reduction current information of the micro-magnetic pole probe.

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