CN117347662A - In-situ sample stage - Google Patents

Abstract

The invention relates to the technical field of sample testing devices, in particular to an in-situ sample table, which comprises: a sample stage body; a sample placing surface, the outer side of which is a sample placing area for placing a sample; a heating component which is arranged on the sample table body and positioned on the inner side of the sample placing surface; and a plurality of solenoids are arranged on the sample stage body, are close to the sample placement surface and circumferentially arranged around the sample placement area, generate magnetic fields with controllable strength after the solenoids are electrified, mutually superpose the magnetic fields of the solenoids at different positions to form a superposition magnetic field, the superposition magnetic field is centrally symmetrical relative to the center of the sample placement area, and the direction of the superposition magnetic field is parallel to the sample placement surface or is positioned in the sample placement surface. The invention integrates the structure capable of generating a temperature field and the structure capable of generating a magnetic field on the in-situ sample stage, and utilizes a limited space to apply temperature and magnetic field to the sample at the same time without shielding the sample.

Description

In-situ sample stage

Technical Field

The invention relates to the technical field of sample testing devices, in particular to an in-situ sample table.

Background

In situ experiments refer to the fact that the whole experimental process of the sample is completed in a microscope, and the change of the sample is observed and recorded in real time as the experiment is carried out. The ex-situ experiment corresponding to the in-situ experiment means that the sample experiment process is completed outside the microscope, and after the experiment is completed, the sample is placed in the microscope for observation. Obviously, the in-situ experiment is closer to the real environment, and can more accurately reflect the structure of the material and the nature of the physical property change.

At the micro-nano level, the materials show remarkable size effect, and when the materials are in different physical fields and external environments, the structures and physical properties of the materials have different evolution. The change of the material can be more accurately observed by adopting an in-situ experiment.

Among the many influencing factors on the material properties, temperature and magnetic field are common factors. The magnetic properties of the material change with temperature. For example, when the material reaches the curie temperature, the spontaneous magnetization in the magnetic material drops to zero, i.e. the ferromagnetic or ferrimagnetic species are converted into paramagnetic species. The magnetic material often has the influence of temperature in the working scene, and the research on the magnetic property change of the magnetic material in a magnetic-thermal composite field is necessary.

In-situ experiments are often performed in an electron microscope, in which a sample cavity is provided, in which an in-situ sample stage for carrying a sample is provided, and in order to apply a physical field to the sample in the in-situ sample stage, a corresponding structure needs to be installed in the sample cavity. However, it is envisioned that the sample chamber is quite limited in size and cannot be configured with both the loading magnetic field and the thermal field. In addition, care must be taken that the sample on the in-situ sample stage is not blocked, which would otherwise affect the observation of the sample.

Disclosure of Invention

The invention aims to provide an in-situ sample stage, wherein a structure capable of generating a temperature field and a structure capable of generating a magnetic field are integrated on the in-situ sample stage, and the temperature and the magnetic field are simultaneously applied to a sample by using a limited space and the sample is not shielded.

To achieve the above object, there is provided an in-situ sample stage comprising:

a sample stage body;

a sample placing surface, the outer side of which is a sample placing area for placing a sample;

a heating component which is arranged on the sample table body and positioned on the inner side of the sample placing surface;

the solenoids are arranged close to the sample placing surface and circumferentially arranged around the sample placing area, magnetic fields with controllable strength are generated after the solenoids are electrified, the magnetic fields of the solenoids at different positions are mutually overlapped to form an overlapped magnetic field, the overlapped magnetic field is symmetrical with the center of the sample placing area in a center mode, and the direction of the overlapped magnetic field is parallel to the sample placing surface.

In some embodiments, the number of solenoids is an even number, the even number of solenoids is paired two by two, and the axes of the two solenoids in the same pair are located on a straight line, and the straight line is parallel to the sample placement surface.

In certain embodiments, an even number of the solenoids are regularly arranged to form a planar pattern, the planar pattern being in the sample placement plane; or even number of solenoids are regularly arranged to form a three-dimensional figure, and the center of the three-dimensional figure is positioned in the sample placing surface.

In some embodiments, when an even number of the solenoids are regularly arranged to form a planar pattern, the planar pattern is a line segment or a square.

In some embodiments, when the planar figure is a line segment, a midpoint of the line segment coincides with a center of the sample placement surface, and the number of solenoids is two; when the planar pattern is square, the center of the square coincides with the center of the sample placement surface, and the number of solenoids is four.

In some embodiments, when an even number of the solenoids are regularly arranged to form a stereoscopic pattern, a center of the stereoscopic pattern is located in the sample placement plane.

In certain embodiments, the number of solenoids is eight and the solid pattern is a cube.

In certain embodiments, the shape, size, and number of turns of each of the solenoids are the same; and/or a metal core is arranged in the solenoid; and/or the number of solenoids is two or four or eight.

In certain embodiments, the same surface of the sample stage body is provided with a first mounting groove and a second mounting groove, the number of the second mounting grooves is matched with the number of the solenoids, the second mounting grooves are arranged around the first mounting groove, the heating component is positioned in the first mounting groove, and the solenoids are positioned in the second mounting groove.

In certain embodiments, the in situ sample stage further comprises:

and two ends of the magnetic yoke are respectively connected with the outer ends of the two solenoids in the same pair.

In some embodiments, the yoke is disposed obliquely.

In certain embodiments, the in situ sample stage further comprises:

a heat conduction member provided outside the heating member, the outer surface of the heat conduction member serving as the sample placement surface;

in certain embodiments, the thermally conductive member is a ceramic sheet.

Compared with the prior art, the invention has the beneficial effects that: the heating component can heat the sample placed on the sample placement surface, the direction of the superimposed magnetic field generated after the plurality of solenoids are electrified is parallel to the sample placement surface, the directions of the superimposed magnetic fields are symmetrical, the plurality of solenoids are opposite to each other and are close to the sample placement surface, so that the superimposed magnetic field can be relatively concentrated near the sample placement surface, the magnetic field utilization rate is improved, and the purposes of simultaneously heating the sample and adding the magnetic field are achieved. In addition, because the heating component is located the opposite direction of sample placement area, can not shelter from the sample, because the solenoid is arranged around sample placement area, also can not shelter from the sample, therefore does not have any shelter from the sample, the convenient sample of observing.

Drawings

Fig. 1 is a perspective view of an in-situ sample stage provided by an embodiment of the present invention.

Fig. 2 is an exploded view of an in situ sample stage according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of an arrangement of eight solenoids according to an embodiment of the present invention.

Fig. 4 is a schematic diagram showing the distribution of superimposed magnetic fields formed by two, four and eight solenoids respectively in a sample placement plane according to an embodiment of the present invention.

In the figure: 1. an electromagnet; 2. a heat conductive member; 3. a heating member; 4. a yoke; 5. a sample stage body; 6. a wiring hole; 7. a heat insulating plate; 8. a first mounting groove; 9. and a second mounting groove.

Detailed Description

The technical scheme of the invention is further described below by the specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the drawings related to the present invention are shown.

In the present invention, directional terms such as "upper", "lower", "left", "right", "inner" and "outer" are used for convenience of understanding, and thus do not limit the scope of the present invention unless otherwise specified.

In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present invention, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

In the present embodiment, the structure of the in-situ sample stage is illustrated by the in-situ sample stage in the transmission electron microscope, but the in-situ sample stage is not limited thereto, and the in-situ sample stage is also applicable to other types of electron microscopes, even optical microscopes.

Fig. 1 is a perspective view of an in-situ sample stage provided by an embodiment of the present invention. Fig. 2 is an exploded view of an in situ sample stage according to an embodiment of the present invention.

Referring to fig. 2, the in-situ sample stage includes a stage body 5. The sample stage body 5 has a substantially flat cylindrical shape. The middle part of the upper surface of the sample stage body 5 is provided with a first installation groove 8 which is concave downwards. The cross section of the first mounting groove 8 may be polygonal including rectangular, or may be circular, elliptical, or the like. The heating member 3 for heating, which is matched with the shape of the first mounting groove 8, is mounted in the first mounting groove 8.

In this embodiment, since the heating part 3 is installed inside the sample stage body 5, the volume of the in-situ sample stage is not increased, and it is ensured that the in-situ sample stage can still be disposed in the sample chamber after the heating part 3 is installed.

In other embodiments, the first mounting groove 8 may not be provided, but the heating member 3 may be provided only on the outer surface of the sample stage body 5, but in this case, the heating member 3 having a smaller volume may be used.

As an example of the heating member 3, the heating member 3 may be a positive temperature coefficient thermistor (Positive Temperature Coefficient, PTC), but is not limited thereto, and may be other members that generate heat using joule heat. The PTC is adopted because the PTC can be continuously adjusted at 20-500 ℃ and provides possibility for providing a larger temperature adjustment range for the sample. In addition, the area of the PTC can be made relatively small, for example, 1 square centimeter, so that the PTC can be smoothly installed inside the sample stage body 5, and interference with a sample cavity inside the scanning electron microscope is avoided.

In some embodiments, the sample may be directly placed on the upper surface of the heating member 3, i.e., the upper surface of the heating member 3 is used as a sample placement surface for placing the sample, so that the sample is not likely to be blocked by the heating member 3 due to the placement of the sample on the upper surface of the heating member 3, and the observation process and the observation result are not affected.

The space above the sample placement surface is defined as the sample placement area, which is also referred to as being formed outside the sample placement surface, since the sample is typically located outside the in situ sample stage, it being understood that in this case the heating means 3 is located inside the sample placement surface.

As shown in fig. 2, considering the disadvantages of PTC such as uneven heating, slow temperature rising rate, and serious temperature drift, in this embodiment, the upper surface of the heating member 3 is provided with the heat conducting member 2, and the upper surface of the heating member 3 is completely covered by the heat conducting member 2, that is, in this embodiment, the upper surface of the heat conducting member 2 is used as a sample placing surface for placing a sample, so as to avoid direct contact between the sample and the heating member 3. The heat conduction part 2 has the function of transferring the heat generated by the heating part 3 to the sample, so that the heat is firstly accumulated on the heat conduction part 2 to uniformly heat the heat conduction part 2, and then the heat is uniformly transferred to the sample by the heat conduction part 2, so that the sample is heated more uniformly, the temperature rising rate and the heat compensation rate are faster, and the non-uniform heating of the surface of the sample is avoided. In addition, the heat conduction component 2 separates the sample from the heating component 3, so that the heating component 3 is prevented from being damaged when the sample is taken and placed.

As an example of the heat conductive member 2, the heat conductive member 2 may be a ceramic sheet, a heat conductive gasket, or the like, but since the heat conductive property of the ceramic sheet is far greater than that of a general heat conductive gasket, the ceramic sheet is preferable as the heat conductive member 2.

As shown in fig. 2, the bottom of the sample stage body 5 is provided with a heat insulating plate 7, the shape of the heat insulating plate 7 is close to that of the sample stage body 5, and in this embodiment, the heat insulating plate 7 is a circular thin plate with the same diameter as the sample stage body 5. The heat insulating plate 7 is made of a material having poor heat conductive property, such as plastic. The purpose of the heat shield 7 is to prevent heat generated when the heating element 2 heats from being conducted downwards, thereby affecting the components in the sample chamber of the scanning electron microscope.

As shown in fig. 2, four second mounting grooves 9 are provided around the circumference of the first mounting groove 8, and the second mounting grooves 9 are also formed to be recessed downward from the upper surface of the sample stage body 5, and in this embodiment, the second mounting grooves 9 are semi-cylindrical, i.e., semi-circular in longitudinal section. The included angle between the two adjacent second mounting grooves 9 is 90 degrees, that is, the axes of the two adjacent second mounting grooves 9 are vertical, so that the second mounting grooves 9 are opposite to each other in pairs, and the four second mounting grooves 9 are paired in pairs, the axes of the two second mounting grooves 9 in the same pair are in a straight line, and the axes of the two second mounting grooves 9 in different pairs are mutually vertical. A solenoid (helically extending wire) is mounted in each second mounting groove 9, i.e. four solenoids, the outer diameter of which matches the diameter of the second mounting groove. The solenoid generates a magnetic field when energized, and the direction of the magnetic field can be determined using the right hand rule. Within the solenoid, the magnetic field direction is approximately parallel to the axis of the solenoid. Outside the solenoid, the direction of the magnetic field extends from one end of the solenoid along a curve toward the other end of the solenoid, and the direction of the extension is opposite to the direction of the magnetic field within the solenoid. A metal core (e.g. iron core) may be provided within the solenoid to strengthen the solenoid into an electromagnet 1 to enhance the strength of the magnetic field within the solenoid to concentrate the magnetic field at the axis of the solenoid. In addition, by changing the magnitude of the current in the solenoid, the strength of the magnetic field generated by the solenoid can be correspondingly changed. Specifically, the magnetic field strength is proportional to the current magnitude. When the current increases, the magnetic field strength increases; when the current decreases, the magnetic field strength decreases.

In this embodiment, the axes of all solenoids are parallel to the sample placement surface, more precisely, the central axes of all solenoids lie in the sample placement surface.

In this embodiment, all solenoids have the same shape, size and number of turns, and when the same amount of current is applied to each solenoid, the magnitude of the magnetic field of each solenoid is the same.

In this embodiment, four solenoids are paired in pairs, the axes of two solenoids in the same pair are aligned, and the axes of two solenoids in different pairs are perpendicular to each other. The outer ends (or other locations, such as axial midpoints) of the four solenoids are interconnected to form a square (planar pattern), the axes of the solenoids corresponding to the diagonal of the square. In addition, each solenoid is uniformly spaced from the midpoint of the sample placement surface.

Therefore, when current is introduced into each solenoid, the superposed magnetic field formed by mutually superposing the magnetic fields generated by each solenoid is strictly limited on the sample placing surface, so that the utilization rate of the magnetic field can be improved, and the influence of the magnetic field on the magnetic lens in the scanning electron microscope can be reduced to the minimum. By varying the magnitude of the current in the solenoids at different positions, the direction of the superimposed magnetic field can be varied accordingly. In this embodiment, the solenoid can generate a magnetic field which is parallel to the sample placement surface and whose magnitude and direction can be continuously changed.

It should be noted that, although four solenoids are used in the present embodiment, in other embodiments, the number of solenoids may be other than four, but the number of solenoids is preferably an even number so as to form a symmetrical superimposed magnetic field.

In one possible embodiment, the number of solenoids is preferably two, four or eight, since these numbers not only enable a symmetrical superimposed magnetic field to be formed, but also enable a relatively easy mounting on the sample stage body 5. When the number of solenoids is six, it is not easy to form a symmetrical superimposed magnetic field. When the number of solenoids is an even number of ten or more, it is not easy to mount such a large number of solenoids on the sample stage body 5.

In the case of two solenoids, it is only necessary to align the axes of the two solenoids so that the line between the two solenoids forms a line segment (planar pattern), which is not specifically described. The midpoint of the line segment is located at the center of the sample placement surface.

The arrangement of eight solenoids may be referred to in fig. 3, in which eight solenoids are respectively disposed on eight vertices of a cube having a side length d, that is, the connection lines between the eight solenoids form a cube (three-dimensional pattern), the axes of the eight solenoids are parallel to each other, and the directions of currents in the respective solenoids are shown by arrows in fig. 3, so that magnetic fields are superimposed on each other at the center point of the cube, and the sample placement surface is a horizontal plane passing through the center of the cube.

Fig. 4 shows a schematic of the distribution of the superimposed magnetic field formed by two, four and eight solenoids in the sample placement plane. Referring to fig. 4, the restriction of the magnetic field by two solenoids is not as strong as four solenoids, but the restriction of eight solenoids is the best, but the installation difficulty of eight solenoids is greatly improved compared with four solenoids, and the required volume of the sample stage body 5 is also greatly increased, which has a great realization difficulty for the limited space of the sample chamber in the scanning electron microscope.

As shown in fig. 2, in order to further restrain the magnetic field in the sample placement surface, a yoke 4 may be mounted on the solenoid, specifically, two yokes 4 are shown in fig. 1 and 2, each yoke 4 is connected to a pair of electromagnets 1, for example, both ends of the yoke 4 are respectively connected to outer ends of the pair of electromagnets 1 and fixed to a sample stage main body 5. The magnetic yoke 4 is a soft magnetic material which does not produce a magnetic field and only transmits magnetic force lines in a magnetic circuit, and the soft magnetic material is easy to magnetize and demagnetize due to the adoption of the soft magnetic material, so that the transmission of magnetic force lines is not influenced. The magnetic yoke 4 is used for restricting the magnetic leakage of the induction coil to diffuse outwards, restricting the distribution of magnetic induction lines and enhancing the magnetic field intensity of a sample plane, and further shielding the magnetic field which is not on the surface of the sample so as to avoid the influence on a magnetic lens in a scanning electron microscope and improve the utilization rate of the magnetic field. The yoke 4 is semi-circular in cross section along the radial direction of the sample stage body 5, and is formed so as to transmit magnetic lines of force.

In order to avoid shielding of the sample by the magnet yoke 4, the magnet yoke 4 is obliquely arranged, specifically, the included angle between the magnet yoke 4 and the normal line of the sample table main body 5 is 40-60 degrees, preferably 55 degrees, the included angle between the ion gun and the electron gun in the double-beam electron microscope is referred to herein, the range of the included angle does not influence the electron beam to reach the surface of the sample, the sample is not shielded, and experimental observation is facilitated.

As shown in fig. 2, the fixing hole 6 is used to fix the terminal of the solenoid and the terminal of the heating member 3 so that an external power source communicates with the solenoid and the heating member 3 through the fixing hole 6.

From the above, the present embodiment can provide a magnetic field parallel to the sample placement surface and continuously variable in size and direction in the in-situ sample stage, so as to heat the sample and apply the magnetic field simultaneously, and study the magnetic properties of the material at different temperatures, so as to further understand the physicochemical properties of the material. The heat conduction part 2 is covered on the heating part 3, so that the temperature rising rate and the thermal compensation rate are faster, the temperature is more uniform, the upper temperature limit is higher, and the risk of manually damaging the heating part 3 in the experimental process is reduced. As shown in fig. 1 and 2, the solenoid and the heating part 3 in the present embodiment are integrated inside the in-situ sample stage, and the volume of the in-situ sample stage is not increased, so that the in-situ sample stage can be smoothly installed in the sample cavity of the electron microscope, and in addition, no shielding exists above the sample placement surface, so that the change of the sample can be conveniently observed.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art. The generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. An in situ sample stage, comprising:

a sample stage body (5);

a sample placing surface, the outer side of which is a sample placing area for placing a sample;

a heating member (3) provided on the sample stage body (5) and located inside the sample placement surface;

the solenoids are arranged on the sample table body (5), are close to the sample placement surface and circumferentially arranged around the sample placement area, and generate magnetic fields with controllable strength after being electrified, the magnetic fields of the solenoids at different positions are mutually overlapped to form an overlapped magnetic field, the overlapped magnetic field is centrally symmetrical relative to the center of the sample placement area, and the direction of the overlapped magnetic field is parallel to the sample placement surface.

2. The in situ sample stage of claim 1, wherein the number of solenoids is an even number, the even number of solenoids are paired in pairs, and the axes of two solenoids in the same pair lie on a straight line that is parallel to or within the sample placement surface.

3. The in situ sample stage of claim 2, wherein an even number of said solenoids are regularly arranged to form a planar pattern, said planar pattern being in said sample placement plane; or even number of solenoids are regularly arranged to form a three-dimensional figure, and the center of the three-dimensional figure is positioned in the sample placing surface.

4. The in situ sample stage of claim 3, wherein when an even number of said solenoids are regularly arranged to form a planar pattern, said planar pattern is a line segment or a square.

5. The in-situ sample stage of claim 4, wherein when the planar pattern is a line segment, a midpoint of the line segment coincides with a center of the sample placement surface, and the number of solenoids is two; when the planar pattern is square, the center of the square coincides with the center of the sample placement surface, and the number of solenoids is four.

6. The in-situ sample stage of claim 3, wherein when an even number of said solenoids are regularly arranged to form a solid pattern, a center of said solid pattern is located in said sample placement surface; preferably, the number of the solenoids is eight, and the three-dimensional pattern is a cube.

7. The in situ sample stage of claim 1, wherein each of the solenoids is identical in shape, size and number of turns; and/or a metal core is arranged in the solenoid; and/or the number of solenoids is two or four or eight.

8. An in situ sample stage according to claim 1, characterized in that the same surface of the sample stage body (5) is provided with a first mounting groove (8) and a second mounting groove (9), the number of second mounting grooves (9) being matched to the number of solenoids, the second mounting grooves (9) being arranged around the first mounting groove (8), the heating element (3) being located in the first mounting groove (8), the solenoids being located in the second mounting groove (9).

9. The in situ sample stage of claim 1, wherein the in situ sample stage further comprises:

the two ends of the magnetic yoke (4) are respectively connected with the outer ends of the two solenoids in the same pair;

preferably, the magnet yoke (4) is arranged obliquely.

10. The in situ sample stage of claim 1, wherein the in situ sample stage further comprises:

a heat conduction member (2) provided outside the heating member (3), the outer surface of the heat conduction member (2) serving as the sample placement surface;

preferably, the heat conductive member (2) is a ceramic plate.