JPH04249054A - Surface microscope - Google Patents

Abstract

PURPOSE:To provide possibility of observation with high resolution in am ultra- cryogenic environment by equipping a surface microscope with a special vibration decreasing function consisting of a spiral metal sheet. CONSTITUTION:A refrigerant vessel 3 for cooling a specimen 14 is fixed to a flange 22, and a reflex board 11 to shield radiation heat is fixed to the periphery of this vessel 3. The end face of a specimen table 10 is coupled with the surface of the vessel 8 by a coupling member made from a circular metal sheet 8 elongated in spiral. form, in which cuts are provided concentrically. Two of such metal sheets 8 are used and installed so that their spirals are directed oppositely. Liquid nitrogen is injected into another refrigerant vessel 1 in order to lessen the quantity of radiation heat given to the first named refrigerant vessel 3 from a vacuums vessel 23. The specimen 14 is cooled by releasing its heat to the refrigerant vessel 3 via the specimen table 10 and metal sheets 8. Thus heat transfer to the specimen 14 can be made while vibrations likely to intrude externally are shielded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface microscope equipped with a sample cooling function.

0002

2. Description of the Related Art Microscopes belonging to surface microscopes include, for example, scanning tunneling microscopes, atomic force microscopes, and magnetic force microscopes. The magnetic force microscope is, for example, Surface Science 189/1.
90 (1987) 29.

[0003] Since this magnetic force microscope was not equipped with a cooling function for the sample, the temperature of the sample during observation was limited to room temperature. Furthermore, since it does not have the function of applying a magnetic field to the sample or the function of supplying electricity, observation of the magnetism of the sample is limited. On the other hand, as a scanning tunneling microscope equipped with a sample cooling function, for example, the 49th Japan Society of Applied Physics Academic Conference (1st
As described in 988) 424, a refrigerant flow path for cooling the sample and a sample stage for holding the sample are integrated, and a refrigerant such as liquid nitrogen is injected into the refrigerant flow path to cool the gap between the refrigerant flow path and the sample. It was cooled by heat conduction.

0004

[Problems to be Solved by the Invention] The magnetic properties and magnetic domain structure of a magnetic sample change depending on temperature. In particular, in order to observe the magnetic domains of each material before and after it reaches the superconducting state, a cooling function is required to cool the sample to an extremely low temperature without transmitting vibrations to it. This is likewise required for scanning tunneling microscopes.

[0005] In the structure of the conventional scanning tunneling microscope equipped with the cooling function described above, the refrigerant flow path and the sample stage are fixed in close contact with each other. is transmitted to the sample, making high-resolution observation difficult. Further, since the fine movement stage and the coolant flow path are integrated, the fine movement stage is also cooled. In this case, the movement of the fine movement stage became unstable, causing a problem in accuracy. When the fine movement stage is mounted on a vibration isolating mechanism that isolates it from vibrations entering from the outside, the vibration isolating mechanism is also naturally cooled. If a polymer material is used for the vibration isolation mechanism, when it is cooled to a low temperature,
There was a problem in that the polymer material hardened and the vibration isolation performance deteriorated, making it impossible to observe the sample.

An object of the present invention is to provide a surface microscope such as a magnetic force microscope or a scanning tunneling microscope, which is equipped with a sample cooling function that cools the sample to an extremely low temperature by blocking vibrations caused by coolant flow, evaporation, etc. do.

[0007]

[Means for Solving the Problems] In order to achieve the above object, a heat transfer member connecting a refrigerant container or a refrigerant flow path and a sample stand that holds a sample loaded on a vibration isolation table, or a part thereof, has a circular metal shape. Thin incisions were made in concentric circles to avoid cutting into thin plates, and these were stretched into a spiral shape for use.

[0008] By connecting the refrigerant container or refrigerant flow path and the sample stage with this thin metal plate, vibrations caused by the flow or evaporation of the refrigerant are not transmitted to the sample stage, and since it is highly movable, it is possible to Can easily follow dimensional movement. Furthermore, since the thin metal plate is used in a spiral shape, there is no strain anisotropy due to low-temperature shrinkage.

[0009]

[Operation] When a sample is fixed on a sample stage and a refrigerant is injected into a refrigerant container or a refrigerant channel, the sample is cooled through the thin metal plate having the above-described structure. At this time, vibrations caused by the flow of refrigerant, evaporation, etc. are blocked by this thin metal plate.

0010

[Embodiments] Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is an external view of a magnetic force microscope according to the present invention.

The magnetic force microscope according to the present invention has a flange 2
2 and placed in a vacuum container 23. The sample 14 is fixed between the sample stage 10 and the cap 13. Sample stand 1
An electromagnet 12 for exciting the sample from about 1E-3 to 1T is housed inside the magnet. The sample stage 10 is fixed and electrically insulated from the fine movement stage 17 in order to supply electricity to the sample 14. A cantilever 16 equipped with a magnetic needle for obtaining magnetic information about the sample and a probe 15 for detecting displacement of the cantilever 16 are mounted on a fine movement stage 17, respectively. Fine movement stage 17 is fixed on base 18. By fixing the base 18 on the vibration isolation mechanism 19,
This blocks vibrations trying to be transmitted to the base 18 from the outside. This vibration isolation mechanism 19 is fixed on the stage 20. The stage 20 is fixed to a flange 22 via a mounting base 21 and placed in a vacuum vessel 23.

A refrigerant container A3 for cooling the sample 14 is fixed to the flange 22 via a pipe 5, and refrigerant is injected through the injection port 4. A reflecting plate 11 is fixed to the outer periphery of the refrigerant container A3 to shield radiant heat from the vacuum container 23 entering the sample stage 10. On the outer periphery of the reflecting plate 11,
The flange 22 is installed so that the refrigerant container B1 does not come into contact with the reflecting plate.
and is fixed via a pipe 6. The refrigerant is injected from the injection port 2.

The end face of the sample stage 10 and the face of the refrigerant container A3 are connected by a thin metal plate 8, which is formed by making concentric narrow notches in a circular thin metal plate and stretched into a spiral shape. Two metal thin plates 8 were used, and they were installed so that the spiral directions were opposite to each other. The metal thin plate 8 is sandwiched and fixed between the refrigerant container A3 and the backing plate 7 in order to improve adhesion. Similarly, the metal thin plate 8 is sandwiched and fixed between the sample stage 10 and the backing plate 9.

In order to reduce the amount of heat radiated from the vacuum container 23 to the refrigerant container A3, an injection port 2 is provided in the refrigerant container B1.
Inject liquid nitrogen from the On the other hand, liquid helium is injected into the refrigerant container A3 from the injection port 4. The sample 14 is cooled by transferring the heat of the sample 14 to the coolant container A3 via the sample stage 10 and the thin metal plate 8.

Although copper is used as the thin metal plate in this embodiment, a thin plate of gold or silver can also be used. FIG. 2 shows an external view of the thin copper plate used in this example with cuts made.

FIG. 3 shows a thin copper plate stretched into a spiral shape.

The sample stage 10 and refrigerant container A are arranged in the shape shown in FIG.
3 are connected.

The thin copper plate having the shape shown in FIG. 3 has extremely low rigidity and is easily displaced by a minute external force. Therefore, vibrations generated from the flange or refrigerant container A3 can be isolated. Furthermore, since the shape has excellent movability, it is possible to easily follow the three-dimensional movement of the sample stage. Furthermore, there is no anisotropy of shrinkage at low temperatures. This thin copper plate is fixed face-to-face with the sample stand, so it is easy to install and has low contact thermal resistance. Furthermore, by moving the refrigerant container until it comes into close contact with the sample stage, the sample can be instantly cooled to an extremely low temperature, and then returned to its original position, thereby making it possible to shorten the observation time.

[0020] With the cooling function constructed as described above, it was possible to cool the sample to about 40K. Further, the sample cooling mechanism using a thin metal plate used in this example can be easily applied to other vibration-averse measuring instruments.

[0021]

[Effects of the Invention] As explained above, according to the present invention, heat can be transferred to the sample while shielding vibrations from entering from the outside, so that a surface microscope capable of high-resolution observation in an extremely low temperature environment can be achieved. is obtained.

[Brief explanation of the drawing]

FIG. 1 is an external view of one embodiment of the present invention.

FIG. 2 is a front view of the thin metal plate shown in FIG. 1 with cuts made therein.

FIG. 3 is a perspective view of the thin metal plate used in FIG. 1.

[Explanation of symbols]

1... Refrigerant container B, 2... Inlet, 3... Refrigerant container A, 4... Inlet, 5... Pipe, 6... Pipe, 7... Backing plate, 8... Metal thin plate, 9... Backing plate, 10... Sample stage, 11...Reflector, 12
...electromagnet, 13...cap, 14...sample, 15...search needle, 16...cantilever, 17...fine movement stage, 18...base, 19...vibration isolation mechanism, 20...stage, 21...attachment base, 22...flange, 23... Vacuum container, 31... Refrigerant channel, 31a... Inlet, 32... Pipe, 31b... Outlet.

Claims (4)

[Claims] Claim 1: A sample stage that holds a sample, a detection medium that approaches the sample and detects a force between the sample and an electric signal between the sample, and a detection medium or sample that is loaded and moves slightly. A surface microscope that operates in a selected special atmosphere and is equipped with a stage, a vibration isolation mechanism that isolates the stage, detection medium, and sample table from vibration, and has a sample cooling function with a special vibration isolation function. A surface microscope featuring: 2. In the cooling mechanism according to claim 1, a heat transfer member or a part thereof that connects the refrigerant container or refrigerant flow path for cooling the sample and the sample stage is provided with a concentric ring formed on a circular thin metal plate. A surface microscope characterized by using a thin metal plate made with thin cuts and stretched into a spiral shape. 3. The surface microscope according to claim 1, characterized in that the cooling mechanism according to claim 2 is provided with a cooling mechanism that is movable until the refrigerant container for cooling the sample or the refrigerant channel comes into close contact with the sample stage. . 4. The surface microscope according to claim 1, which has a function of applying a magnetic field to a sample and a function of supplying electricity.