Diamond anvil and its manufacturing method and use method

Abstract

To prevent a diamond anvil from being damaged due to the influence of an X ray when irradiating the diamond anvil with the X ray for a long time in the state of applying ultra-high pressure (for example, a pressure of approximately 150 GPa) on a sample by a diamond anvil.SOLUTION: A diamond anvil 20 for pressurizing a sample includes a diamond main body 10 and a CVD diamond film 21 formed on the surface of the main body 10. The main body 10 has a tip surface 11 equivalent to a place for arranging the sample, and the CVD diamond film 21 is formed in a region including at least the tip surface 11 in the surfaces of the main body 10.SELECTED DRAWING: Figure 4A

Description

[Technical field]

[0001] The present invention relates to a diamond anvil for applying high pressure to a sample. [Background technology]

[0002] In order to measure the physical properties (electrical resistance, X-ray scattering spectrum, etc.) of a sample under ultra-high pressure conditions, a high pressure is applied to the sample using a diamond anvil. A diamond anvil is a roughly conical body with a small tip surface, and can be obtained by cutting and polishing a natural diamond, for example.

[0003] Such a pair of diamond anvils are arranged with their tip faces facing each other, and with a sample sandwiched between the tip faces, high pressure is applied to the pair of diamond anvils to press them against each other. This applies ultra-high pressure (for example, 150 GPa to 200 GPa) to the sample. By measuring the physical properties of the sample to which ultra-high pressure is applied in this way, it is possible to measure the physical properties of the sample under ultra-high pressure conditions and to explore new functions of the sample.

[0004] For example, when hydrogen sulfide solidified with liquid nitrogen was used as a sample and subjected to ultra-high pressure of about 150 GPa as described above and its electrical resistance was measured as a physical property, it was discovered that hydrogen sulfide exhibits a high superconducting transition temperature exceeding absolute temperature 200 K.

[0005] The diamond anvil is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2018-128286 A Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, when a sample (e.g., solidified hydrogen sulfide) is subjected to a pressure of about 150 GPa using a diamond anvil and its physical properties (e.g., X-ray scattering spectrum) are measured by continuously irradiating the sample with X-rays for a long period of time (e.g., about 12 hours), there is a problem that the diamond anvil may be damaged by the effects of the X-rays.

[0008] The present invention has been made to solve this problem. That is, an object of the present invention is to suppress damage to the diamond anvil due to the influence of X-rays when the diamond anvil is irradiated with X-rays for a long period of time while applying ultrahigh pressure (for example, a pressure of about 150 GPa) to a sample by the diamond anvil. [Means for solving the problem]

[0009] In order to achieve the above object, according to the present invention, there is provided a diamond anvil for applying pressure to a sample, comprising: A diamond anvil is provided having a diamond body and a CVD diamond film formed on a surface of the body.

[0010] According to the present invention, there is also provided a method for manufacturing a diamond anvil for applying pressure to a sample, the method comprising the steps of: (A) Prepare the diamond body. (B) A method for manufacturing a diamond anvil is provided, which comprises forming a CVD diamond film on the surface of the main body by chemical vapor deposition to obtain a diamond anvil having the main body and the CVD diamond film. Effect of the Invention

[0011] According to the present invention, a CVD diamond film is formed on the surface of a diamond body, which makes it possible to prevent the diamond anvil from being damaged when the sample and diamond anvil are irradiated with X-rays for a long period of time while ultra-high pressure is applied to the sample using the diamond anvil. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a side view showing an example of a diamond anvil to which the present invention can be applied. [Diagram 2] FIG. 1 is an explanatory diagram of a case where a sample is pressurized using a pair of diamond anvils. [Figure 3A-3D] This is an actual image of a diamond anvil in which a crack has occurred, viewed from its tip face side. [Figure 4A] FIG. 1 is a side view showing a configuration of a diamond anvil according to an embodiment of the present invention. [Figure 4B] 4B-4B in FIG. 4A. [Figure 5A-5B] FIG. 2 is a schematic diagram of an example of a crystal structure in which diamond crystals are oxygen-terminated on the surface of a CVD diamond film. [Figure 6A-6B] FIG. 2 is a schematic diagram of an example of a crystal structure in which diamond crystals are hydrogen-terminated on the surface of a CVD diamond film. [Figure 7] 1 is a flowchart showing a method of manufacturing a diamond anvil according to an embodiment of the present invention. [Figure 8A] 1 is an image of the tip face of a diamond anvil according to an embodiment, observed from the back side before X-ray irradiation. [Figure 8B] 1 is an image of the tip face of a diamond anvil according to an embodiment, observed from the back side after irradiation with X-rays. [Figure 9A] 1 is an image of the tip face of a diamond anvil according to a comparative example, observed from the back side before X-ray irradiation. [Figure 9B] 1 is an image of the tip face of a diamond anvil according to a comparative example, observed from the back side after being irradiated with X-rays. [Figure 10] FIG. 4B shows the case where a mark is provided on the surface of the diamond anvil. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. In the drawings, the same reference numerals are used to designate the same parts, and duplicated explanations will be omitted.

[0014] (Diamond anvil to which the present invention can be applied) FIG. 1 is a side view showing an example of a diamond anvil 10 to which the present invention can be applied. The diamond anvil 10 is used to apply high pressure to a sample. The diamond anvil 10 has a tip face 11, an inclined surface 12 on the tip face 11 side, and a base portion 13 located on the opposite side to the tip face 11. The tip face 11 is a surface (also called a curette) on which the sample is placed when the sample is pressurized by the diamond anvil 10. The base portion 13 has a bottom surface 15 facing the opposite side to the tip face 11.

[0015] The diamond anvil 10 has a shape in which the cross-sectional area gradually increases from the tip surface 11 to the base portion 13. In this case, the inclined surface 12 extends from the tip surface 11 to the base portion 13 of the diamond anvil 10 in a direction inclined (for example, greater than 45 degrees) relative to the central axis C of the diamond anvil 10 so as to move away from the central axis C, and also extends in the circumferential direction around the central axis C to complete one revolution.

[0016] The above cross-sectional area is the area of ​​a cross section taken along a virtual plane perpendicular to the central axis C of the diamond anvil 10. The central axis C faces from the base portion 13 toward the tip surface 11. The tip surface 11 and the bottom surface 15 may be planes perpendicular to the central axis C.

[0017] In the diamond anvil 10, the shape of the portion from the tip surface 11 to the boundary between the inclined surface 12 and the base portion 13 may be substantially conical, for example, a polygonal pyramid with a cut tip (a regular hexagonal pyramid, for example). The tip surface 11 may be a surface having a dimension (for example, a diameter) of about 10 μm or more and 1 mm or less, but is not limited to this dimension.

[0018] Fig. 2 is an explanatory diagram of a case where a sample is pressurized using a pair of the above-mentioned diamond anvils 10. In Fig. 2, each diamond anvil 10 is shown as viewed from the side, and a gasket 14, which will be described later, is shown as a cross section taken along a plane including the central axis C of the diamond anvil 10.

[0019] As shown in FIG. 2, a pair of diamond anvils 10 are arranged so that the tip surfaces 11 face each other, and a sample is arranged between the tip surfaces 11. At this time, the sample (not shown) may be arranged using a gasket 14. The gasket 14 is a plate-shaped sealing member with a through hole formed in the center. With the sample arranged in the through hole, the gasket 14 is arranged between both tip surfaces 11 together with the sample. In this state, a load is applied to the bottom surface 15 of each diamond anvil 10 toward the tip surface 11 of the diamond anvil 10 using a pressure mechanism (not shown). As a result, the sample is sandwiched between the tip surfaces 11 of the pair of diamond anvils 10, and an ultra-high pressure (for example, 150 GPa to 200 GPa) is applied to the sample. At this time, the gasket 14 is in close contact with the diamond anvil 10 even when it is deformed, thereby preventing the sample from coming off the tip surface 11.

[0020] Each diamond anvil 10 in Fig. 2 is obtained by cutting a natural diamond and polishing the surface of the cut diamond. If an X-ray is continuously irradiated onto a sample (e.g., solidified hydrogen sulfide) for a long period of time (e.g., about 12 hours) to measure the physical properties (e.g., X-ray scattering spectrum) of the sample under ultrahigh pressure (150 GPa to 200 GPa) as shown in Fig. 2, the diamond anvil 10 will be damaged by the influence of the X-ray.

[0021] A diamond anvil 10 damaged in this manner is shown in Fig. 3A to Fig. 3D. Fig. 3A to Fig. 3D are actual images of the diamond anvil 10 viewed from the tip surface 11 side. As shown in Fig. 3A to Fig. 3D, the diamond anvil 10 has numerous cracks and is damaged. In Fig. 3A to Fig. 3D, the diamond anvil 10 appears opaque due to the influence of the illumination light.

[0022] (Configuration of the embodiment of the present invention) A diamond anvil 20 according to an embodiment of the present invention for suppressing such breakage will be described. Fig. 4A is a side view showing the configuration of the diamond anvil 20 according to the embodiment of the present invention. Fig. 4B is a view taken along the line 4B-4B of Fig. 4A.

[0023] The diamond anvil 20 according to this embodiment is obtained by forming a CVD diamond film 21 on the surface of the above-mentioned diamond anvil 10. That is, the above-mentioned diamond anvil 10 that is not being used to pressurize a sample is used as the diamond main body, and the CVD diamond film 21 is formed on the surface of this main body 10 to form the diamond anvil 20 of this embodiment. In this embodiment, the surface of the CVD diamond film 21 is not polished, so that there are, for example, few or almost no polishing marks (such as ultra-fine cracks on the nanometer order, which will be described later) on this surface.

[0024] According to this embodiment, a CVD diamond film 21 may be formed as a synthetic (i.e., artificial) diamond film on at least the entire tip surface 11 (the tip surface corresponding to the location where a sample is placed) on the surface of the main body 10. In one example, as shown in FIG. 3A, a CVD diamond film 21 may be formed on the tip surface 11 and the inclined surface 12 (e.g., the entire tip surface 11 and the inclined surface 12) on the surface of the main body 10. The thickness of the CVD diamond film 21 may be, for example, 10 nm or more and 100 nm or less (40 nm or less in one example). In this case, the upper limit of the thickness of the CVD diamond film 21 may be about several hundred nm.

[0025] The surface of the portion of the CVD diamond film 21 formed on the tip surface 11 becomes the new tip surface 21a of the diamond anvil 20. In this case, the surface of the portion of the CVD diamond film 21 formed on the inclined surface 12 becomes the new inclined surface 21b of the diamond anvil 20. The inclined surface 21b extends from the tip surface 21a to the base 13 of the diamond anvil 20 in a direction inclined (for example, greater than 45 degrees) relative to the central axis C of the diamond anvil 20, as well as extending in a circumferential direction around the central axis C to complete one revolution, similar to the inclined surface 12. The diamond anvil 20 has the same shape as the diamond anvil 10 described above. That is, in the diamond anvil 20, the shape of the portion from the tip surface 21a to the boundary between the inclined surface 21b and the base 13 may be substantially conical, for example, may be a prefixed pyramid shape obtained by cutting the tip of a polygonal pyramid (for example, a regular hexagonal pyramid).

[0026] In addition, the diamond crystals constituting the surface (for example, the entire surface) of the CVD diamond film 21 may be oxygen-terminated. That is, in the diamond crystals constituting the surface of the CVD diamond film 21, oxygen atoms may be bonded to each dangling bond of a carbon atom.

[0027] Alternatively, the diamond crystals constituting the surface (for example, the entire surface) of the CVD diamond film 21 may be hydrogen-terminated. That is, in the diamond crystals constituting the surface of the CVD diamond film 21, a hydrogen atom may be bonded to each dangling bond of a carbon atom.

[0028] Figures 5A and 5B are schematic diagrams of crystal structure examples in which diamond crystals are oxygen-terminated on the surface of the CVD diamond film 21. In Figures 5A and 5B, each white circle represents a carbon atom, and each circle with a diagonal line represents an oxygen atom. In Figures 5A and 5B, the upper side is the surface side of the CVD diamond film 21. As in the case of Figure 5B, a cross-link may be formed by oxygen atoms bonded to dangling bonds of the diamond crystals that constitute the surface of the CVD diamond film 21.

[0029] 6A and 6B are schematic diagrams of crystal structure examples in which diamond crystals are hydrogen-terminated on the surface of a CVD diamond film 21. In Fig. 6A and Fig. 6B, the larger white circles represent carbon atoms, and the smaller white circles represent hydrogen atoms. In Fig. 6A and Fig. 6B, the upper side is the surface side of the CVD diamond film 21.

[0030] It should be noted that the specific form in which the diamond crystals are oxygen-terminated or hydrogen-terminated on the surface of the CVD diamond film 21 is not limited to the examples shown in FIGS. 5A to 6B.

[0031] (Manufacturing method of diamond anvils) 7 is a flowchart showing a method for manufacturing the diamond anvil 20 according to an embodiment of the present invention. The manufacturing method according to this embodiment includes steps S1 to S4.

[0032] In step S1, a diamond body 10 is prepared. For example, in step S1, the above-mentioned diamond anvil 10 shown in Fig. 1 is prepared as the diamond anvil body 10. In one example, the body 10 prepared in step S1 is obtained by cutting a diamond (e.g., a natural single crystal diamond) into a predetermined shape (e.g., a substantially conical shape) and polishing the surface of the cut diamond of the desired shape.

[0033] In step S2, hydrogen plasma is brought into contact with the surface of the main body 10 (e.g., the entire tip surface 11 and the entire inclined surface 12). Step S2 may be performed as follows. The main body 10 is placed in a vacuum chamber. Next, the inside of the vacuum chamber is evacuated with a vacuum pump to create a vacuum inside the vacuum chamber. Thereafter, hydrogen gas is introduced into the chamber in a vacuum state to generate hydrogen plasma. This hydrogen plasma may be generated, for example, by introducing microwaves into the vacuum chamber.

[0034] The hydrogen plasma thus generated is brought into contact with the surface of the main body 10 (for example, by irradiating the surface of the main body 10 with hydrogen plasma), thereby cleaning the surface. This makes it possible to remove defective parts on the surface of the main body 10. Here, the defective parts may be, for example, parts with poor crystallinity, parts where hydrogen or oxygen is bonded, or fine cracks. In one example of the processing conditions for step S2, the energy (strength) of the microwaves introduced into the chamber is about 750 W, the flow rate and pressure of the hydrogen gas introduced into the chamber are about 300 sccm and about 35 torr, respectively, the processing temperature (surface temperature of the main body 10) is about 800° C., and the processing time is about 5 minutes. However, the processing conditions for step S2 are not limited to these.

[0035] After step S2 is completed, the hydrogen plasma generation intensity is reduced, for example by reducing the microwave intensity (intensity per unit area) described above. This reduced hydrogen plasma generation intensity state is maintained until step S3, described below, is completed. That is, until step S3 is completed, the introduction of hydrogen gas and microwaves into the vacuum chamber is continued to maintain a hydrogen plasma atmosphere inside the vacuum chamber. The vacuum state created by the reduced pressure inside the vacuum chamber is also maintained until step S3 is completed.

[0036] In step S3, a chemical vapor deposition (CVD) method is used to form a CVD diamond film 21 on the surface of the main body 10. In this embodiment, in step S3, a CVD diamond film 21 is formed on an area of ​​the surface of the main body 10 that includes at least the entire tip face 11 (for example, the entire tip face 11 and the entire inclined face 12) by the CVD method.

[0037] Step S3 may be performed as follows. A hydrocarbon gas (e.g., methane gas) is further introduced into the vacuum chamber in which the main body 10 is placed. This hydrocarbon functions as a carbon source to grow a diamond film (i.e., the above-mentioned CVD diamond film 21) on the surface of the main body 10. When the thickness of this diamond film becomes sufficient (e.g., about 10 nm to 40 nm), step S3 is terminated. For example, the introduction of the hydrocarbon gas into the inside of the vacuum chamber is stopped, the generation of the above-mentioned hydrogen plasma is stopped, and the decompression inside the vacuum chamber is stopped. Note that, as an example of the processing conditions for step S3, the energy of the microwaves introduced into the chamber is about 250 W, the flow rate and pressure of the hydrogen gas introduced into the chamber are about 300 sccm and about 35 torr, respectively, and the methane gas (CH 4 The flow rate of the gas 3 is about 0.2 sccm, the processing temperature (the surface temperature of the main body 10) is about 600° C., and the processing time is about 2 hours. However, the processing conditions of step S3 are not limited to these.

[0038] Since the surface of the CVD diamond film 21 formed in step S3 has been in contact with hydrogen plasma, the diamond crystals constituting the surface are hydrogen-terminated. That is, on the surface of the CVD diamond film 21, a hydrogen atom is bonded to each dangling bond of a carbon atom, as shown in FIG. 6A or 6B.

[0039] In step S4, an oxygen termination process is performed to convert the hydrogen terminations on the surface of the CVD diamond film 21 to carbon terminations. As a result, the diamond crystals constituting the surface of the CVD diamond film 21 are in a state in which an oxygen atom is bonded to each dangling bond of a carbon atom, as shown in FIG. 5A or 5B.

[0040] In step S4, for example, the diamond anvil 20 having the body 10 and the CVD diamond film 21 formed on the surface of the body 10 may be taken out of the vacuum chamber and subjected to oxygen termination treatment. By subjecting the CVD diamond film 21 to oxygen termination treatment, the diamond crystals constituting the surface of the CVD diamond film 21 are converted from a hydrogen-terminated state to an oxygen-terminated state.

[0041] The oxygen termination treatment may be, for example, a treatment in which the diamond anvil 20 is placed in a mixed solution of sulfuric acid and nitric acid, and the mixed solution is heated. In one example of the conditions for the oxygen termination treatment, the mixture ratio of nitric acid to sulfuric acid (nitric acid / sulfuric acid) is about 1 / 3, the temperature of the mixed solution is about 200°C, and the treatment time is about 30 minutes. However, the conditions for the oxygen termination treatment are not limited to these. In addition, the oxygen termination treatment is not limited to the treatment using the above mixed solution, and may be other treatments. For example, the oxygen termination treatment may be a treatment in which the CVD diamond film 21 formed on the body 10 is exposed to high-concentration ozone or oxygen plasma.

[0042] (Effects of this embodiment) In this embodiment, a CVD diamond film 21 is formed on the surface of the diamond anvil 20 in an area including at least the tip face 11. This makes it possible to prevent the diamond anvil 20 from being damaged by irradiating the sample and diamond anvil 20 with X-rays for a long period of time while applying ultrahigh pressure (e.g., 150 GPa to 200 GPa) to the sample using the diamond anvil 20.

[0043] The details are as follows. When the CVD diamond film 21 is not formed on the diamond body 10, the surface of the body 10 is mechanically polished, and therefore there is a possibility that extremely small cracks (for example, about 1 nm to 500 nm) on the order of nanometers may occur on the surface. Therefore, in this embodiment, the CVD diamond film 21 is formed on the surface of the body 10. Since extremely small cracks due to mechanical polishing do not occur in the diamond crystal on the surface of the CVD diamond film 21, it can be said that the diamond crystal on the surface is in good condition. As a result, when X-rays are irradiated on the diamond anvil 20 for a long time while applying ultra-high pressure to the sample by the diamond anvil 20 on which the CVD diamond film 21 is formed on the surface of the body 10 as described above, it is possible to suppress the damage of the diamond anvil 20 due to the influence of X-rays.

[0044] As described above, the diamond crystals constituting the surface of the CVD diamond film 21 may be oxygen-terminated. In this case, as shown in FIG. 5B, a cross-linking bond may be formed by oxygen atoms bonded to the dangling bonds of the diamond crystals. This further stabilizes the diamond crystal structure on the surface of the CVD diamond film 21. As a result, the damage to the diamond anvil 20 as described above can be further suppressed.

[0045] (Example) In this embodiment, a pair of diamond anvils 20 were prepared according to the above-mentioned flow chart of Fig. 7. As described above, each of the pair of diamond anvils 20 has a CVD diamond film 21 formed on its surface (tip face 11 and inclined face 12), and the diamond crystals constituting the surface of the CVD diamond film 21 are oxygen-terminated.

[0046] In addition, using the pair of diamond anvils 20 described above, an experiment was conducted in which ultra-high pressure was applied to a sample, as shown in Fig. 2. In this experiment, solidified hydrogen sulfide was used as the sample, and while applying ultra-high pressure of 145 GPa to the sample, the diamond anvils 20 were irradiated with X-rays with an energy of 18 keV for more than 36 hours.

[0047] Actual images of the diamond anvil 20 before and after the X-ray irradiation are shown in Fig. 8A and Fig. 8B, respectively. Fig. 8A and Fig. 8B are images of the front end surface 21a of the diamond anvil 20 observed from the back surface 15 side. Fig. 8A and Fig. 8B show the state in which ultra-high pressure is applied to the sample by the diamond anvil 20. As shown in Fig. 8B after X-ray irradiation, the diamond anvil 20 was not damaged by the above-mentioned experiment.

[0048] (Comparative Example) On the other hand, in the comparative example, a pair of diamond anvils 10 were prepared by cutting and polishing natural diamond. These pair of diamond anvils 10 were the same as the diamond body 10 prepared in step S1 described above, and no CVD diamond film 21 was formed on their surfaces.

[0049] Using the pair of diamond anvils 10 thus prepared, an experiment was carried out in which ultra-high pressure was applied to a sample, as shown in Fig. 2. In this experiment, solidified hydrogen sulfide was used as the sample, and while applying ultra-high pressure of 135 GPa to the sample, the diamond anvils 10 were irradiated with X-rays with an energy of 18 keV for about 24 hours.

[0050] Actual images of the diamond anvil 10 before and after the X-ray irradiation are shown in Fig. 9A and Fig. 9B, respectively. Fig. 9A and Fig. 9B are images of the diamond anvil 10, observed from its rear surface 15 at the tip surface 11. Fig. 9A and Fig. 9B show the state in which ultra-high pressure is applied to the sample by the diamond anvil 20. As shown in Fig. 9B after the X-ray irradiation, the diamond anvil 10 was broken due to cracks caused by the above-mentioned experiment. This damage is considered to be caused by nanocracks on the surface of the diamond anvil 10. For example, it is considered that when hydrogen sulfide is compressed, hydrogen is generated and enters the cracks, and the hydrogen bonds unfavorably with the dangling bonds of the diamond crystal structure, resulting in a weakened crystal.

[0051] As can be seen from the above-mentioned examples and comparative examples, by forming the CVD diamond film 21 on the surface of the main body 10, damage to the diamond anvil 20 can be suppressed. This is believed to be because the diamond on the surface of the CVD diamond film 21 has no nanocracks and has good crystallinity. In addition, the diamond crystals constituting the surface of the CVD diamond film 21 are oxygen-terminated, which further strengthens the crystals and is expected to further suppress damage to the diamond anvil 20.

[0052] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the technical concept of the present invention. For example, the diamond anvil 20 according to the embodiment of the present invention does not have to have all of the above-mentioned features, and may have only some of the above-mentioned features.

[0053] Also, any one of the following modified examples 1 to 4 may be adopted, or any combination of two or more of modified examples 1 to 4 may be adopted. In this case, the points not described below are the same as those described above.

[0054] (Change example 1) The diamond anvil 20 of the present invention may be one in which a CVD diamond film 21 is formed on the surface of a body 10 obtained by cutting an artificially produced synthetic diamond and polishing its surface.

[0055] (Change example 2) The diamond anvil 20 of the present invention may be any type that applies pressure to a sample by sandwiching the sample between its tip surface 21a and another diamond. The other diamond may be the same as the diamond anvil 20, or may be a diamond of a different shape (e.g., a diamond in the form of a substrate). A CVD diamond film may also be formed on the surface of the diamond of a different shape.

[0056] (Change example 3) The process of forming the CVD diamond film 21 on the surface of the diamond anvil 10 is not limited to the above-described example.

[0057] (Modification Example 4) It is difficult to distinguish between the diamond anvil 20 with the CVD diamond film 21 formed on its surface and the diamond anvil 10 without the CVD diamond film 21 based on their structures. Therefore, a mark for indicating that the CVD diamond film 21 is formed may be formed as a local recess of an arbitrary predetermined shape on the surface (inclined surface 21b) of the CVD diamond film 21. The predetermined shape may be a neat shape or a characteristic shape (for example, a T shape) that is shown to be artificially formed so that the mark can be distinguished from scratches or the like. FIG. 10 shows the case where the mark 22 is provided in FIG. 4B.

[0058] The above-described predetermined shape of the mark 22 means the shape (substantially rectangular in FIG. 10) as viewed from a direction perpendicular to the surface (for example, the inclined surface 21b) of the CVD diamond film 21 at the position of the mark 22. Also, the dimensions of the mark 22 (dimensions in each direction along the surface of the CVD diamond film 21) may be on the order of sub-micrometers or on the order of micrometers (for example, 0.1 μm or more and 10 μm or less), but are not limited thereto. The depth of the recess as the mark 22 is the same as the above-described thickness of the CVD diamond film 21. Here, the depth may be the depth in a direction perpendicular to the surface of the CVD diamond film 21 at the position of the mark 22.

[0059] The mark 22 can be provided as follows. Before forming the CVD diamond film 21 on the surface of the diamond anvil 10 (for example, before the above-mentioned step S2), a metal mask (metal micro-part) for the minute mark 22 is provided at a local position (for example, one location) on the surface (for example, the inclined surface 12) of the diamond body 10. That is, a metal mask (metal micro-part) is provided at a local position on the surface (for example, the inclined surface 12) of the body 10, and in this state, the CVD diamond film 21 may be formed on the surface of the body 10 (for example, the above-mentioned steps S2 to S4 may be performed). Since the CVD diamond film 21 is not formed on the metal mask, the mark 22 of any shape can be provided as a recess on the surface (for example, the inclined surface 21b) of the diamond anvil 20 by dissolving the metal mask in acid after the formation of the CVD diamond film 21.

[0060] The metal mask may be formed on the inclined surface 12 that does not affect the generation of pressure, for example, by using lithography. The metal mask may have an area of, for example, 1 μm 2 The metal mask has a rectangular shape of about 100 nm and a thickness of about 100 nm. Here, the rectangular shape refers to the shape when viewed from a direction perpendicular to the surface of the diamond anvil 20 (for example, the inclined surface 21b) at the position of the metal mask, and the thickness refers to the thickness in the perpendicular direction. However, the area, shape, and thickness of the metal mask are not limited to the above example.

[0061] In this fourth modified example, by confirming the presence of the mark 22, it is possible to identify the diamond anvil 20 as one on which the CVD diamond film 21 is formed. [Explanation of symbols]

[0062] 10 Diamond anvil (main body) 11 Apical surface (curette) 12 Slope 13 Base 14 Gasket 15 Bottom 20 Diamond Anvil 21 CVD diamond film 21a Tip surface 21b Slope 22 Mark (recess) C center axis

Claims

1. A method for manufacturing a diamond anvil for pressing a sample, comprising the steps of: (A) Prepare a diamond body; (B) forming a CVD diamond film on the surface of the body by chemical vapor deposition to produce a diamond anvil having the body and the CVD diamond film; A method for manufacturing a diamond anvil, comprising the steps of: before (B), contacting the surface of the body with hydrogen plasma.

2. A method for manufacturing a diamond anvil for pressing a sample, comprising the steps of: (A) Prepare a diamond body; (B) forming a CVD diamond film on the surface of the body by chemical vapor deposition to produce a diamond anvil having the body and the CVD diamond film; The method for producing a diamond anvil further comprises, after (B), carrying out an oxygen termination treatment for oxygen-terminating diamond crystals constituting the surface of the CVD diamond film.

3. 3. The method for producing a diamond anvil according to claim 2, further comprising contacting the surface of the body with hydrogen plasma before (B).

4. 2. The method for producing a diamond anvil according to claim 1, further comprising the step of: after (B), performing an oxygen termination treatment for oxygen-terminating diamond crystals constituting the surface of said CVD diamond film.

5. The body has a tip surface corresponding to a location where a sample is placed, 5. The method for manufacturing a diamond anvil according to claim 1, wherein in (B), the CVD diamond film is formed on a region of the surface of the body that includes at least the tip face.

6. 6. The method for manufacturing a diamond anvil according to claim 1, wherein the main body is obtained by cutting a diamond into a predetermined shape and polishing a surface of the cut diamond of the predetermined shape.

7. Before (B), a metal mask is provided at a localized position on the surface of the body; (B) is performed while the metal mask is provided at the local position; 7. The method for producing a diamond anvil according to claim 1, further comprising the steps of: after (B), dissolving the metal mask in an acid to form marks as localized depressions of a predetermined shape on the surface of the CVD diamond film.

8. A method for using a diamond anvil manufactured by the manufacturing method according to any one of claims 1 to 7, comprising the steps of: A method for using a diamond anvil, comprising the steps of: irradiating a sample, which is pressed by the diamond anvil and has an unpolished surface of the CVD diamond film, with X-rays.

9. A diamond anvil for pressing a sample, A diamond body and a CVD diamond film formed on a surface of the body, The diamond crystal constituting the surface of the CVD diamond film is oxygen-terminated with oxygen atoms bonded to each dangling bond of a carbon atom without any hydrogen termination being present.

Images