JP7729593B2 - Pressurizing device, and microscopic Raman scattering measurement device, X-ray diffraction device, and optical microscope device using the same - Google Patents

Description

The present invention relates to a pressure device and a measurement device using the same, and more specifically to an ultra-high pressure pressure device using a diamond anvil cell.

In many cases, pressure is still applied to diamond anvil cells (DACs) by manually screwing them in using spring force, which requires pressure and position adjustment each time data is collected on crystal structure, including lattice compressibility, in X-ray diffraction and Raman scattering measurements, resulting in a loss of data accuracy.

Furthermore, the pressure generating range exceeding 1,000,000 atmospheres is limited to an extremely small area due to the nature of the generating principle, requiring precise skill. Furthermore, the higher the maximum target pressure, the steeper the pressure-load curve becomes, making pressure control more difficult. Therefore, several attempts have been made to achieve continuous pressure using automatic pressure generation (see, for example, non-patent documents 1-3).

For example, Non-Patent Document 1 discloses a method of applying pressure by attaching a pulse motor to a lever-type DAC that utilizes the principle of leverage. Non-Patent Document 2 discloses a method of applying pressure to a DAC using a gas pressure membrane that uses high-pressure gas such as helium gas. More recently, Non-Patent Document 3 discloses a pressure method that uses a piezoelectric actuator.

Conventional methods using spring force or screws require pressure to be applied each time, lacking continuity of pressure and affecting data density. Pressurization using a gas pressure membrane, as described in Non-Patent Document 2, requires the use of high-pressure gas. The membrane is irreversibly damaged when the anvil breaks, making it difficult to reuse. There is a delay in the expansion of the membrane due to gas pressure control, and there are limits to its ability to follow pressure.

Mechanical pressure methods using pulse motors, etc., as in Non-Patent Document 1, make it difficult to secure an X-ray window, so indirect pressure based on the principle of leverage is required, and pulse control is also limited. Furthermore, pressure applied solely using a piezoelectric actuator, as in Non-Patent Document 3, has a limited stroke, and efficient pressure application is hindered unless the pressure application start point is known. Because typical piezoelectric actuators do not have holes that allow X-rays to pass through, it is difficult to conduct X-ray diffraction experiments under high pressure.

H. -K. Mao, et al., Theory and Practice-Diamond-Anvil Cells and Probes for High PT Mineral Physics Studies, Chapter December 2007, DOI: 10.1016/B978-044452748-6/00037-7 Stanislav V. Sinogeikin et al., Rev. Sci. Instrument. 86,072209 (2015) W. J. Evans et al., Review of Scientific Instruments 78, 073904 (2007)

Based on the above, the objective of the present invention is to provide a pressure device that enables continuous pressure application up to ultra-high pressures, and a measurement device using the same.

The pressure applying device for applying pressure to a sample according to the present invention, as shown in Figures 1 and 2, comprises a diamond anvil cell 110 for clamping the sample S, a pressing mechanism 120 for mechanically applying pressure to the diamond anvil cell 110, an actuator 130 for applying pressure to the diamond anvil cell 110 using an electrical signal, and a pressure sensor 140 for detecting the pressure applied by the actuator 130 to the diamond anvil cell 110, thereby solving the above-mentioned problems.
The pressing mechanism may be selected from the group consisting of a stepper motor, a hydraulic piston device, and a gas pressure membrane device.
The actuator may be a stacked piezoelectric actuator.
The actuator may be hollow.
The stroke of the actuator may be in the range of 50 μm to 200 μm.
The pressure sensor may be a piezoelectric quartz sensor.
The pressure sensor may further include a control mechanism for controlling operations of the pressing mechanism, the actuator, and the pressure sensor.
The control mechanism may control the operation of the pressing mechanism, the actuator, and the pressure sensor so that, for example, as shown in Figure 4, (A) the pressing mechanism applies pressure to the diamond anvil cell, (B) while the pressing mechanism is applying pressure to the diamond anvil cell, the pressure sensor measures the pressure value applied by the actuator and adjusts the actuator to be at the pressure starting point, and (C) while the pressing mechanism is applying pressure to the diamond anvil cell, the actuator adjusted to the pressure starting point continuously applies pressure to the diamond anvil cell.
The control mechanism may control the operation of the pressing mechanism, the actuator, and the pressure sensor so that, for example, as shown in Figure 4, (D) when the actuator is applying pressure to the diamond anvil cell, the pressing mechanism applies further pressure to the diamond anvil cell, (E) when the pressing mechanism is applying further pressure to the diamond anvil cell, the pressure sensor measures the pressure value applied by the actuator and adjusts the actuator to be at the pressure starting point, and (F) when the pressing mechanism is applying further pressure to the diamond anvil cell, the actuator adjusted to the pressure starting point applies pressure to the diamond anvil cell.
The control mechanism may control the operations of the pressing mechanism, the actuator, and the pressure sensor so as to repeat the operations (D), (E), and (F).
The control mechanism may include an actuator drive circuit that applies a voltage to the actuator, a conversion measurement unit that converts and measures the pressure of the pressure sensor, a motor drive circuit that sends a drive current to the pressing mechanism, and a central processing unit that controls the actuator drive circuit, the conversion measurement unit, and the motor drive circuit.
The device may further include a function generator connected to the actuator drive circuit.
The device may further include a controller connected to the motor drive circuit.
A bearing may further be provided between the diamond anvil cell and the actuator.
The microscopic Raman scattering measurement apparatus according to the present invention includes the above-described pressure device, thereby solving the above-described problems.
The X-ray diffraction apparatus according to the present invention includes the above-mentioned pressure device, thereby solving the above-mentioned problems.
The optical microscope apparatus according to the present invention includes the above-described pressure device, thereby solving the above-described problems.
1, in the pressure device for applying pressure to a sample according to the present invention, preferably, a pressing mechanism 120 has a rotary table 125 driven by a stepping motor 121, the rotary table 125 has a hollow portion through which an actuator 130 passes, and the pressing mechanism 120 has a recessed storage chamber 127 for accommodating the end of the actuator 130 that passes through the hollow portion 125a of the rotary table 125. With this configuration, the actuator 130 can be accommodated in the recessed storage chamber provided in the pressing mechanism, and the diamond anvil cell can be attached at a lower position, facilitating combination with, for example, a microscopic Raman scattering measurement device, an X-ray diffraction device, or an optical microscope device.

The pressure device of the present invention is equipped with an actuator, allowing continuous pressure application to the sample in the diamond anvil cell. Furthermore, because it is equipped with a pressing mechanism that mechanically applies pressure, it is possible to maintain a long stroke by combining continuous pressure application by the actuator with stepwise large pressure application by the pressing mechanism, making it possible to apply continuous pressure up to ultra-high pressures. In particular, because it is equipped with a pressure sensor, it detects the pressure applied by the actuator to the diamond anvil cell and makes it possible to identify the actuator's pressure start point. As a result, continuous pressure application up to ultra-high pressures such as 350 GPa is possible while preventing damage to the diamond anvil cell. If the pressure device of the present invention is installed in an X-ray diffraction instrument or a micro-Raman scattering instrument, it can provide highly accurate measurement data even under high pressures.

1 is a schematic diagram showing a pressurizing device of the present invention, with a portion thereof shown in cross section. Schematic diagram showing diamond anvils FIG. 1 is a block diagram showing an embodiment of a control mechanism for a pressure device according to the present invention. A flowchart showing the operation control of the pressing mechanism 120, the actuator 130, and the pressure sensor 140 by the control mechanism of the pressure device of the present invention. Graph showing the relationship between the voltage applied to the piezoelectric actuator and the pressure (A), and the relationship between the load and the pressure detected by the pressure sensor (B). A diagram showing the relationship between the voltage and pressure applied to the piezoelectric actuator (A), and the relationship between the number of executions and the change in applied pressure (B).

Embodiments of the present invention will be described below with reference to the drawings. Note that like elements are numbered likewise and their description will be omitted.

The pressure device of the present invention will now be described.
FIG. 1 is a schematic diagram showing a pressurizing device of the present invention, with a portion thereof shown in cross section.
FIG. 2 is a schematic diagram showing a diamond anvil.

The pressure device 100 of the present invention comprises a diamond anvil cell 110 that holds the sample S, a pressing mechanism 120 that mechanically applies pressure to the diamond anvil cell 110, an actuator 130 that applies pressure to the diamond anvil cell 110 using an electrical signal, and a pressure sensor 140 that detects the pressure applied by the actuator 130 to the diamond anvil cell 110. By using the mechanical pressing mechanism 120 and the actuator 130 in combination, the pressure device 100 of the present invention can continuously apply pressure to the sample up to ultra-high pressures such as 350 GPa.

Figure 2 shows an enlarged view of the diamond anvil 210 inside the diamond anvil cell 110. The pair of diamond anvils 210 clamp the sample S via a gasket 220. The tip of the diamond anvil 210 is flat, and the smaller the area, the greater the load applied to the sample S. The sample S may be held together with a pressure medium substance such as sodium chloride (NaCl). The pair of diamond anvils 210 are clamped between a lower pedestal and an upper pedestal and attached to a jig.

The diamond anvil 210 transmits light in an extremely wide wavelength range, from 220 nm to terahertz, millimeter waves, and even microwaves. Therefore, for example, it is possible to heat the sample S under high pressure by irradiating it with an infrared laser from above the diamond anvil 210. Furthermore, by irradiating X-rays from below the diamond anvil 210, it is possible to measure the X-ray diffraction pattern of the sample S under high pressure. Alternatively, it is possible to irradiate monochromatic light from above the diamond anvil 210 and measure the Raman scattering spectrum of the sample S under high pressure.

The pressing mechanism 120 mechanically applies pressure to the diamond anvil cell 110. In this specification, "mechanically applying pressure" refers to applying pressure to the diamond anvil cell 110 in stages using the principle of leverage, spring force, screw force, etc.

The rotary table housing 120, which serves as the pressing mechanism 120, houses a stepping motor 121, a manual dial 122, a cylindrical storage chamber peripheral wall 123, a cylindrical storage chamber bottom plate 124, a recessed storage chamber 127, and a push pin 128. The rotary table 125 and shell engagement portion 126 are exposed on the top surface of the rotary table housing 120. A push pin insertion hole 129 is provided along the bottom plate of the cylindrical storage chamber bottom plate 124 for inserting the push pin 128.

The manual dial 122 is used in place of the stepping motor 121 to operate the rotation of the turntable 125. The cylindrical housing chamber peripheral wall 123 and the cylindrical housing chamber bottom plate 124 form a partition of the cylindrical housing chamber surrounding the recessed housing chamber 127, and accommodate a pressure sensor 140 and the end of the actuator 130 facing the pressure sensor 140. The cylindrical housing chamber peripheral wall 123 and the cylindrical housing chamber bottom plate 124 are structured to also be used as part of the turntable housing 120. A push pin 128 is inserted through a push pin insertion hole 129 and presses against the lower cover 134. The push pin 128 holds the turntable housing 120 and the cylinder tube 131 together via the lower cover 134, the cylindrical connecting portion 132, and the threaded portion 133.
The rotary table 125 has a hollow central portion 125a, which has an inner diameter that allows the cylinder tube 131 to pass through. One end of the shell engaging portion 126 is attached to the rotary table 125, and the other end is attached to the engaging surface of the cylinder tube 131. The engaging surface of the cylinder tube 131 is, for example, a flat surface formed on the circumferential surface of the cylinder tube 131, and is provided in, for example, four locations on the circumferential surface. The shell engaging portion 126 may be, for example, a combination of two V-shaped blocks each having a V-notch groove formed therein, so that it can easily engage with the engaging surface of the cylinder tube 131. The V-shaped blocks are attached with the V-notch groove surface abutting against the engaging surface of the cylinder tube 131.

The rotational motion of the stepping motor 121 is converted into the rotational motion of the rotary table 125 by a movement guide, such as a cross roller bearing (not shown). The engagement between the rotary table 125 and the cylinder tube 131 is configured so that the rotational motion of the rotary table 125 is converted into the extension and contraction of the cylinder tube 131 via the shell engagement portion 126.

As a result, the rotational motion of the stepping motor 121 rotates the motor shaft by a fixed angle at a time, and the cylinder tube 131 expands and contracts via the rotary table 125 in conjunction with the motor's rotation angle, mechanically compressing or decompressing the diamond anvil cell 110. Using a rotary table with a stepping motor is advantageous because it allows for precise, stepwise pressure application by setting the angle.

In this embodiment, a stepping motor is used, but a hydraulic piston device or gas pressure membrane device may also be used. These allow pressure to be applied using the principle of leverage, spring force, screw force, or a hydraulic/gas pressure booster. When using a hydraulic piston device or gas pressure membrane device, it is recommended to use it in conjunction with a booster.

There are no particular limitations on the actuator 130, as long as it can convert an external electrical signal into physical expansion and contraction movement. A typical example is a piezoelectric element that converts voltage as an electrical signal into force. A stacked piezoelectric actuator may be used. A stacked piezoelectric actuator can expand and contract in the range of several nanometers to several hundred micrometers when a voltage is applied, depending on the number of layers of the piezoelectric element. This expansion and contraction on the order of nanometers enables continuous pressure application, which differs from the pressing mechanism 120.

For example, the pressure applied to the diamond anvil cell 110 corresponding to an elongation of several μm corresponds to only 0.1% of the pressure applied when the pressing mechanism 120, which is a stepping motor, is rotated 1°. In other words, by using the pressing mechanism 120 and the actuator 130 together, the minimum pressure step applied by the pressing mechanism 120 can be filled with a 0.1% step. In this way, continuous pressure application is possible.
Such piezoelectric elements are made of thin films of lead zirconate titanate (PZT, Pb(Zr, Ti)O ₃ ), potassium niobate (KNN, (K, Na)NbO ₃ ), or the like.

There is no limit to the stroke of the actuator 130 (i.e., the maximum extension/contraction range). If the stroke is short, it is sufficient to control the interlocking with the pressing mechanism 120 more, and if the stroke is long, it is sufficient to control the interlocking with the pressing mechanism 120 less. The stroke of the actuator 130 is preferably in the range of 50 μm to 200 μm. Within this range, a pressure device capable of continuous pressure application up to ultra-high pressures (up to 350 GPa) can be provided without the need for a special actuator. In particular, actuators with a stroke in the range of 60 μm to 100 μm are easily available.

The actuator 130 is preferably hollow, as shown in Figure 1. This allows for combining various light sources, such as X-rays and lasers, with a light-receiving unit, making it possible to measure X-ray diffraction patterns, Raman scattering spectra, and the like.

The actuator 130 may be loaded into a cylinder tube 131 engaged with the pressing mechanism 120, and the position of the actuator 130 can be adjusted within the cylinder tube 131 as the actuator 130 expands or contracts. The diamond anvil cell 110 is engaged at the upper end of the cylinder tube 131, allowing the pressure from the pressing mechanism 120 and the pressure from the actuator 130 to be efficiently applied to the diamond anvil cell 110.

The circumferential surface of the cylinder tube 131 is provided with a flat surface for engaging with the shell engaging portion 126. A cylindrical connecting portion 132 is attached to the lower end of the cylinder tube 131. A female thread is formed on the inner circumferential surface of the cylindrical connecting portion 132 as a screw portion 133, which screws into a male thread formed on the outer circumferential surface of the lower end of the cylinder tube 131. A thread is formed on the lower end circumferential surface of the cylindrical connecting portion 132 for screwing in a lower cover portion 134. The lower cover portion 134 covers a pressure sensor 140 provided on the lower end side of the actuator 130.

Although not shown, a bearing may be provided between the diamond anvil cell 110 and the actuator 130. This reduces friction in the rotational direction that occurs between the underside of the diamond anvil cell 110 and the actuator 130. As a result, damage to the actuator due to shear stress can be prevented.

There are no particular limitations on the pressure sensor 140 as long as it detects the pressure applied by the actuator 130 to the diamond anvil cell 110, and examples include a quartz pressure sensor, a strain gauge pressure sensor, a semiconductor pressure sensor, etc. Among these, a quartz piezoelectric sensor that utilizes the piezoelectric effect is preferred because it can measure high loads and can be used repeatedly.
Here, the pressure sensor 140 is provided between the lower end of the actuator 130 and the rotary table 125, but since it is only necessary to detect the pressure applied by the actuator 130 to the diamond anvil cell 110, it may also be provided on the diamond anvil cell 110 side of the actuator 130.

The pressure sensor 140 detects the pressure value applied by the actuator 130 to the diamond anvil cell 110. The actuator 130 is adjusted so that the pressure value applied by the actuator 130 is 0 and the point at which the pressure value begins to be detected is the actuator 130's pressurization start point. The actuator 130 is adjusted by adjusting the applied voltage and position. Continuous pressure is always possible from the set pressurization start point by the stroke of the actuator 130.

Naturally, by using the pressure sensor 140, it is possible to detect when the stroke of the actuator 130 is at its maximum value and set the pressurization end point. It is also possible to continuously reduce the pressure by the stroke of the actuator 130 from the set pressurization end point.

1, the pressure device 100 of the present invention preferably includes a control mechanism 150 that controls the operations of the pressing mechanism 120, the actuator 130, and the pressure sensor 140. This allows automatic continuous pressure application up to ultra-high pressure (350 GPa).
The control mechanism 150 and the stepping motor 121 of the pressing mechanism 120 are connected by a motor drive line 151. The control mechanism 150 and the actuator 130 are connected by an actuator drive line 152. The control mechanism 150 and the pressure sensor 140 are connected by a sensor connection line 153.

Figure 4 is a flowchart showing the operation control of the pressing mechanism 120, actuator 130, and pressure sensor 140 by the control mechanism of the pressure device of the present invention. The control mechanism 150 preferably controls the operation of the pressing mechanism 120, actuator 130, and pressure sensor 140 as follows:

Operation (A): First, the pressing mechanism 120 applies mechanical pressure to the diamond anvil cell 110. For example, if the pressing mechanism 120 is a stepping motor, the motor can be rotated by a predetermined angle.

Operation (B): Next, with the pressing mechanism 120 applying pressure, the pressure sensor 140 detects the pressure applied by the actuator 130 to the diamond anvil cell 110, and the control mechanism 150 adjusts the actuator 130 so that it begins to detect this pressure value. At this time, the stroke of the actuator 130 is preferably 0, meaning that it is not extended at all. In this way, the pressure starting point of the actuator 130 is set.

For example, when the actuator 130 is applying pressure, the applied voltage is adjusted to set the stroke of the actuator 130 to 0, just before pressure is applied. For example, when the actuator 130 is not applying pressure, the position of the actuator 130 within the cylinder tube 131 is adjusted to set it to just before pressure is applied. In this case, the stroke of the actuator 130 is also 0.

Operation (C): Next, while the pressing mechanism 120 is applying pressure, the actuator 130, adjusted to the pressure application start point, continuously applies pressure to the diamond anvil cell 110. For example, if the actuator 130 is a stacked piezoelectric actuator, pressure can be applied to the diamond anvil cell 110 by the stroke of the actuator 130 simply by gradually applying voltage, but by controlling the amount of expansion and contraction of the actuator 130, pressure can be applied precisely within the stroke.

Following the above-described operations (A) to (C) of the pressing mechanism 120, actuator 130, and pressure sensor 140, the control mechanism 150 repeats the application of pressure by the pressing mechanism 120 and the application of pressure by the actuator 130, thereby continuously applying pressure up to ultra-high pressure (e.g., 350 GPa) to the sample.

The operations following controlling the actuator 130 so that the actuator 130 continuously applies pressure to the diamond anvil cell 110 (operation (C)) will now be described in detail.

Operation (D): With the actuator 130 applying pressure to the diamond anvil cell 110, the control mechanism 150 causes the pressing mechanism 120 to apply further pressure to the diamond anvil cell 110. For example, if the actuator 130 is a stacked piezoelectric actuator and the pressing mechanism 120 is a stepping motor, the motor can be further rotated by a predetermined angle while maintaining the voltage applied to the stacked piezoelectric actuator. This brings the actuator 130 and diamond anvil cell 110 physically closer together, so that further pressure from the actuator 130 is applied to the diamond anvil cell 110.

Incidentally, prior to operation (D), the voltage to the actuator 130 may be removed to reduce the pressure applied to the diamond anvil cell 110. This reduction in pressure may also be performed continuously for the stroke of the actuator 130.

Operation (E): Next, with the pressing mechanism 120 applying further pressure, the pressure sensor 140 detects the pressure applied by the actuator 130 to the diamond anvil cell 110 and adjusts the actuator 130 so that it begins to detect the pressure value. This operation (E) is similar to operation (B) described above.

Operation (F): Next, with the pressing mechanism 120 applying further pressure, the actuator 130, adjusted to the pressure starting point again, continuously applies pressure to the diamond anvil cell 110. Operation (F) is similar to operation (C), but the pressure applied by the pressing mechanism 120 is different. Therefore, by controlling the amount of expansion and contraction of the actuator 130 within the new pressure range, it is possible to apply pressure precisely.

In this way, by repeating operations (D) through (F), pressure can be continuously applied up to ultra-high pressure (e.g., 350 GPa). Using the device of the present invention, it is possible to apply pressure until the diamond anvil 210 breaks, and it is also possible to identify the end point of the breakage. While the operation of pressurizing up to ultra-high pressure has been described here, those skilled in the art will readily understand that it is also possible to continuously depressurize from ultra-high pressure by using the maximum value of the stroke of the actuator 130 as the depressurization starting point, rather than the pressurization starting point where the stroke of the actuator 130 is 0, and then performing the reverse operation.

Figure 3 is a block diagram showing one embodiment of the control mechanism of the pressure device of the present invention.

The control mechanism 150 preferably includes an actuator drive circuit 310 that applies voltage to the actuator 130, a conversion measurement unit 320 that converts and measures the pressure of the pressure sensor 140, a motor drive circuit 330 that sends a drive current to the pressing mechanism 120, and a central processing unit 340 that controls the actuator drive circuit 310, the conversion measurement unit 320, and the motor drive circuit 330. This makes it possible to increase pressure up to ultra-high pressure using the above-mentioned operations (A) to (F), or vice versa, to decrease pressure from ultra-high pressure.

A function generator 350 may also be connected to the actuator drive circuit 310. This allows the actuator drive circuit 310 to amplify a pulse voltage having the waveform (pulse signal) of the electrical signal output from the function generator 350 and apply it to the actuator 130. In other words, a voltage can be continuously applied to the actuator 130 according to the pulse width, allowing for continuous pressure increase or decrease. For example, if a 1 Hz pulse voltage is used, a voltage can be applied at a 1 second cycle, allowing for periodic pressure increase or decrease. The function generator may also be a pulse generator. The actuator drive circuit 310 may also have a voltage amplification function that amplifies and outputs the pulse voltage.

There are no particular limitations on the conversion measurement unit 320, as long as it converts the pressure of the pressure sensor 140 into an electrical signal such as an amount of charge and measures it. For example, a charge amplifier can be used as the conversion measurement unit 320.

The motor drive circuit 330 sends a drive current to the pressing mechanism 120 to operate it, and is preferably connected to a controller (not shown) that provides a pulse signal to the motor drive circuit 330. This allows the torque of the stepping motor to be adjusted by adjusting the frequency of the pulse signal, enabling angle control.

The central processing unit 340 sets the frequency of the pulse signal generated by the controller and outputs to the controller a control signal to cause the controller to output the set pulse signal, as well as a control signal to cause the controller to stop outputting the pulse signal. As a result, the pressing mechanism 120 is driven by the motor drive circuit 330 based on the pulse signal from the controller, mechanically applying pressure to the diamond anvil cell 110. Needless to say, the pressure applied to the diamond anvil cell 110 can be reduced depending on the frequency of the pulse signal.

The central processing unit 340 reads the electrical signal converted by the conversion measurement unit 320 and adjusts the actuator 130 to be at the pressure application start point. The central processing unit 340 reads the electrical signal, sets the frequency of the pulse signal generated by the function generator 350, and outputs to the function generator 350 a control signal for causing the function generator 350 to output the set pulse signal, as well as a control signal for causing the function generator 350 to stop outputting the pulse signal.

Here, if the central processing unit 340 determines that the actuator 130 is in a pressurized state, it sets the stroke of the actuator 130 to 0 and sets a pulse signal so that it is just about to be pressurized. If it determines that the actuator 130 is not in a pressurized state, it adjusts the position of the actuator 130 inside the cylinder tube 131 and outputs a control signal to a position adjustment unit (not shown) so that it is just about to be pressurized. In this way, the pressurization start point of the actuator 130 is adjusted. Note that instead of using the position adjustment unit, the user may manually adjust the position of the actuator 130.

Alternatively, the central processing unit 340 may set the pulse signal so that the maximum value of the stroke of the actuator 130 is the pressure reduction start point. In this case, continuous pressure reduction is possible.

Once the pressure application start point for the actuator 130 is set, the central processing unit 340 sets the frequency of the pulse signal generated by the function generator 350 and outputs to the function generator 350 a control signal for causing the function generator 350 to output the set pulse signal, as well as a control signal for causing the function generator 350 to stop outputting the pulse signal. As a result, the actuator 130 applies pressure to the diamond anvil cell 110 continuously, for example, in 0.1% steps relative to the pressure applied by the pressing mechanism 120.

The central processing unit 340 may be equipped with a memory (not shown) that stores a program for repeatedly applying mechanical stepwise pressure using the pressing mechanism 120 and applying fine continuous pressure using the actuator 130. This allows automatic pressure application up to ultra-high pressure (e.g., 350 GPa) and pressure reduction from ultra-high pressure. Furthermore, pulse signals for the pressing mechanism 120 and the actuator 130 may be set via an input device (not shown) such as a keyboard or touch panel, and these settings may be recorded in memory.

Such a central processing unit 340 may be configured using hardware logic, or may be realized using software using a personal computer equipped with a CPU (Central Processing Unit).

As described above, by equipping the pressure device 100 of the present invention with various light sources, X-ray sources, light receiving units for receiving scattered light or diffracted light, etc., an X-ray diffraction device or a microscopic Raman scattering measurement device can be constructed. Furthermore, by mounting the pressure device 100 of the present invention on a microscope, an optical microscope device capable of observing samples under high pressure can be provided. Naturally, multiple of these various measurement devices may be combined.

The present invention will now be described in detail using specific examples, but please note that the present invention is not limited to these examples.

[Example 1]
In Example 1, a mixture of gold and scandium nitride (ScN) was placed in a beveled diamond anvil cell 110 with a tip of 0.04 mm in the pressure device 100 shown in Figure 1, and the change in pressure applied to the sample was examined. The pressing mechanism 120 was a stepping motor with a motor drive circuit 330 and a controller (ARS-136-HP, manufactured by Chuo Seiki Co., Ltd.), and the actuator 130 was a hollow laminated piezoelectric actuator (HPSt 1000/25-15/80 VS35, lead zirconate titanate, stroke length: 80 μm, manufactured by Piezosystem Jena GmbH). Hereinafter, this will be referred to simply as the piezoelectric actuator. The pressure sensor 140 was a quartz piezoelectric sensor (CLP/62KN, manufactured by HBK).

The piezoelectric actuator was connected to a piezoelectric actuator amplifier (SVR 1000, manufactured by Piezosystem Jena GmbH) and a function generator 350 (WF1973, manufactured by NF Corporation) as the actuator drive circuit 310, which were then connected to a personal computer equipped with a CPU as the central processing unit 340.

The quartz piezoelectric sensor was connected to a piezoelectric sensor amplifier (HBK, CMD600) as the conversion measurement unit 320, and then connected to a computer via an Ethernet hub. Pressure changes were determined from the lattice constant of gold using X-ray diffraction (see, for example, Taku Tsuchiya, JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. B10, 2462, 2003).

A quartz crystal sensor was attached to the bottom of the cylinder tube, which had the piezoelectric actuator attached, and the bottom lid was closed. The cylinder tube was fixed to a pressing mechanism (stepping motor). The sample was loaded into the diamond anvil cell, and the diamond anvil cell was screwed into the cylinder's top screw while applying appropriate pressure with the diamond anvil cell's top screw 111 (Figure 1).

Next, the stepping motor was activated to mechanically apply pressure to the diamond anvil cell. The pressure starting point of the piezoelectric actuator was adjusted using a quartz piezoelectric sensor. After that, a pulse signal (voltage) generated by the function generator was input to the piezoelectric actuator amplifier, and a voltage 120 times larger than the original voltage was supplied to the piezoelectric actuator, extending the actuator and pressurizing the diamond anvil cell. Figure 4 shows the pressure change on the sample obtained in this way.

Figure 5 shows the relationship between the voltage applied to the piezoelectric actuator and the pressure (A), and the relationship between the load and the pressure detected by the pressure sensor (B).

Figure 5 shows that by using an actuator adjusted to start applying pressure at 38 GPa, it is possible to continuously apply pressure from 38 GPa to 130 GPa. The piezoelectric actuator makes it possible to conduct ultra-high pressure experiments at pressure increments of 0.1%, even under ultra-high pressures exceeding 100 GPa.

Next, when the supply voltage of the piezo actuator amplifier reached its maximum voltage due to pressure applied by the piezo actuator (i.e., when the piezo actuator was extended to its maximum stroke), the stepping motor was rotated 5 to 10° to apply further pressure to the diamond anvil cell. Note that the voltage to the piezo actuator may be removed before applying pressure to the stepping motor.

At this point, the pressure application start point of the piezoelectric actuator was again adjusted using the quartz piezoelectric sensor. Next, from the point at which the quartz piezoelectric sensor began to respond, voltage was supplied to the piezoelectric actuator and pressure application began. By repeating this process, it was confirmed that pressure could be applied up to 311 GPa without the diamond anvil breaking.

[Example 2]
In Example 2, a mixture of gold and NaCl was placed in a flat diamond anvil cell 110 with a tip diameter of 0.3 mm in the pressure device 100 shown in Figure 1, and the change in pressure applied to the sample was measured. The change in pressure was determined from the Raman scattering spectrum of the diamond (e.g., Yuichi Akahama et al., Journal of Applied Physics 96, 3748, 2004).

In Example 2, as in Example 1, mechanical pressure was applied using a stepping motor, the pressure starting point of the piezoelectric actuator was adjusted, continuous pressure was applied for the stroke of the piezoelectric actuator, and then continuous pressure reduction of the piezoelectric actuator was performed, and these processes were repeated. The pressure changes on the sample obtained in this way are shown in Figure 5.

Figure 6 shows the relationship between the voltage and pressure applied to the piezoelectric actuator (A), and the relationship between the number of runs and the change in applied pressure (B).

Figure 6(A) shows that by using a piezoelectric actuator and a stepping motor in combination, it is possible to continuously apply pressure up to 50.1 GPa. Note that in Example 2, unlike Example 1, the contact area with the sample is larger, resulting in a different ultimate pressure.

In Figure 6(A), the curves for the pressure application process (behavior 1 in the figure) and the pressure application process (behavior 2 in the figure) of the piezoelectric actuator are not on the same line. This is due to the hysteresis of the expansion and contraction of the piezoelectric actuator and the deformation of the sample chamber during pressure application. Even if the sample chamber becomes thinner due to pressure application, the stroke can be advanced by the stepping motor, allowing pressure to be applied in stages and continuously.

[Example 3]
Example 3 is the same as Example 1 except that a beveled diamond anvil cell with a tip of 0.06 mmφ was used in the pressure device 100 of Figure 1, so a description thereof will be omitted. Similarly to Example 1, when a stepping motor and a piezo actuator were used in combination, it was confirmed that continuous pressure up to 250 GPa could be applied. The diamond anvil then broke during pressure application. From this, it was determined that the end point (breaking point) of a diamond anvil with this tip size was 250 GPa.

The pressure device of the present invention can continuously apply pressure up to ultra-high pressures, allowing for the collection of highly accurate data. Furthermore, the pressure device of the present invention can pinpoint the end point of diamond destruction, preventing damage to the anvil and making it an effective ultra-high pressure pressure device. Furthermore, the pressure device of this example can continuously apply pressure up to ultra-high pressures of 350 GPa.

100 Pressurizing device 110 Diamond anvil cell 111 Upper screw 120 Pressing mechanism (housing for rotary table)
121 Stepping motor 122 Manual dial 123 Cylindrical storage chamber peripheral wall 124 Cylindrical storage chamber bottom plate 125 Rotary table 125a Hollow portion 126 Shell engagement portion 127 Recessed storage chamber 128 Push pin 129 Push pin insertion hole 130 Actuator 131 Actuator shell 132 Cylindrical connecting portion 133 Threaded portion 134 Lower cover portion 140 Pressure sensor 150 Control mechanism 151 Motor drive line 152 Actuator drive line 153 Sensor connection line 210 Diamond anvil 310 Actuator drive circuit 320 Conversion measurement unit 330 Motor drive circuit 340 Central processing unit 350 Function generator

Claims (17)

A pressure device that applies pressure to a sample,
a diamond anvil cell that holds the sample;
a pressing mechanism that mechanically applies pressure to the diamond anvil cell;
an actuator that applies pressure to the diamond anvil cell by an electric signal;
a pressure sensor that detects the pressure applied to the diamond anvil cell by the actuator ;
The pressing mechanism is selected from the group consisting of a stepping motor, a hydraulic piston device, and a gas pressure membrane device . The pressing mechanism has a rotary table driven by the stepping motor,
the rotary table has a hollow portion through which the actuator passes,
The pressure device according to claim 1 , wherein the pressing mechanism includes a recessed accommodation chamber that accommodates an end of the actuator that passes through a hollow portion of the rotary table. 3. The pressure device according to claim 1 , wherein the actuator is a stacked piezoelectric actuator. The pressure device according to any one of claims 1 to 3 , wherein the actuator is hollow. The pressure device according to any one of claims 1 to 4 , wherein the stroke of the actuator is in the range of 50 μm to 200 μm. The pressure device according to any one of claims 1 to 5 , wherein the pressure sensor is a quartz piezoelectric sensor. The pressure device according to claim 1 , further comprising a control mechanism for controlling operations of the pressing mechanism, the actuator, and the pressure sensor. The control mechanism
(A) the pressing mechanism applies pressure to the diamond anvil cell;
(B) while the pressing mechanism applies pressure to the diamond anvil cell, the pressure sensor measures the pressure value applied by the actuator, and adjusts the actuator to be at the pressure start point;
(C) while the pressing mechanism applies pressure to the diamond anvil cell, the actuator adjusted to the pressure starting point continuously applies pressure to the diamond anvil cell.
The pressure device according to claim 7 , wherein operations of the pressing mechanism, the actuator, and the pressure sensor are controlled so as to The control mechanism
(D) while the actuator is applying pressure to the diamond anvil cell, the pressing mechanism applies further pressure to the diamond anvil cell;
(E) while the pressing mechanism applies further pressure to the diamond anvil cell, the pressure sensor measures the pressure value applied by the actuator, and adjusts the actuator to be at the pressure start point;
(F) in a state where the pressing mechanism applies further pressure to the diamond anvil cell, the actuator adjusted to the pressure starting point applies pressure to the diamond anvil cell.
The pressure device according to claim 8 , wherein operations of the pressing mechanism, the actuator, and the pressure sensor are controlled so as to The pressure device according to claim 9 , wherein the control mechanism controls operations of the pressing mechanism, the actuator, and the pressure sensor so as to repeat the operations (D), (E), and (F). The control mechanism
an actuator drive circuit that applies a voltage to the actuator;
a conversion/measurement unit that converts and measures the pressure of the pressure sensor;
a motor drive circuit for sending a drive current to the pressing mechanism;
The pressure device according to any one of claims 7 to 10 , further comprising: a central processing unit that controls the actuator drive circuit, the conversion measurement unit, and the motor drive circuit. The pressure device according to claim 11 , further comprising a function generator connected to the actuator drive circuit. The pressure device according to claim 11 or 12 , further comprising a controller connected to the motor drive circuit. A pressure device that applies pressure to a sample,
a diamond anvil cell that holds the sample;
a pressing mechanism that mechanically applies pressure to the diamond anvil cell;
an actuator that applies pressure to the diamond anvil cell by an electric signal;
a pressure sensor that detects the pressure applied to the diamond anvil cell by the actuator;
a control mechanism for controlling the operations of the pressing mechanism, the actuator, and the pressure sensor;
Equipped with
The control mechanism
(A) the pressing mechanism applies pressure to the diamond anvil cell;
(B) while the pressing mechanism applies pressure to the diamond anvil cell, the pressure sensor measures the pressure value applied by the actuator, and adjusts the actuator to be at the pressure start point;
(C) while the pressing mechanism applies pressure to the diamond anvil cell, the actuator adjusted to the pressure starting point continuously applies pressure to the diamond anvil cell;
The pressure device controls the operations of the pressing mechanism, the actuator, and the pressure sensor so as to A microscopic Raman scattering measurement device equipped with the pressure device described in any one of claims 1 to 14. An X-ray diffraction apparatus equipped with the pressure device described in any one of claims 1 to 14. An optical microscope apparatus equipped with the pressure device described in any one of claims 1 to 14.