JP2001242231A - Magnetic field generating device and magnetic resonance force microscope using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic resonance force microscope capable of providing sample information on the surface of a sample or a micro area on the surface of the sample while permitting wide area scanning. SOLUTION: This magnetic field generating device 1 for the magnetic resonance force microscope 12 is provided with a solenoid coil 2 and a cylindrical magnetic substance 5 of high permeability translational along the center symmetry axis of the coil 2. In the magnetic dipole magnetic field generated by the magnetic field generating device 1, magnetic field intensity larger than the maximum magnetic field generated by the coil 2 is obtained without impairing the spatial uniformity of the magnetic field. The sample 39 is set into the magnetic dipole magnetic field and irradiated with high frequency by an RF coil 20 to make magnetic moment of the sample 39 magnetically resonant. A cantilever 18 is flexurally vibrated at the magnetic field gradient formed by a magnetic chip 19 through the magnetic resonance, and the flexural vibration is detected through an optical fiber 25. The magnetic field generating device 1 is moved in a narrow scanning area by a piezoelectric element 14, and the sample 39 is moved in a wide range by a coarse adjustment driving part 37.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a magnetic field generator having a solenoid coil and generating a magnetic field intensity larger than the magnetic field intensity generated by the solenoid coil, and using the magnetic field generator. , Magnetic resonance force microscope (Magnetic Resonace Force Micr) that uses a magnetic resonance phenomenon to image a very small area of a sample
oscopy (hereinafter also referred to as MRFM).

[0002]

2. Description of the Related Art Conventionally, there has been a magnetic resonance method as one of the methods for observing a sample. In this magnetic resonance method, a large number of magnetic moments are stored in a high-frequency coil placed in a static magnetic field having high spatial uniformity. This was a bulk measurement in which a sample containing the sample was set, and a high-frequency magnetic field was applied to the sample to resonate the magnetic moment of the sample to measure the entire sample.

[0003]

By the way, such a magnetic resonance measurement requires a magnetic field having high spatial uniformity of 10 ^-5 or more within 1 cm ³ . For this reason, conventionally, measurement has been performed with a sample placed at the center of a solenoid type coil or a pole piece type electromagnet that creates a magnetic field, and further, correction is made around the main coil to improve the uniformity of the center. Winding a coil has been performed. However, there has been no method for improving the magnetic field uniformity of the coil end face without losing the strength.

On the other hand, a new scanning probe microscope, so-called MRFM, for imaging a very small area of a sample by combining respective element technologies of a magnetic resonance method (NMR / ESR) and an atomic force microscope (AFM), For example, it is proposed in Japanese Patent Publication No. 7-69280.

[0005] This MRFM is a solenoid for generating a static magnetic field having a required magnetic field strength at a sample position to generate a magnetic moment in the sample in the direction of a polarized field (magnetic polarization field). A high-frequency coil, a modulating means for supplying a modulation signal for modulating a polarization field (magnetic polarization field) to the high-frequency coil, a magnetic chip disposed opposite to the sample to generate a magnetic field gradient, A cantilever that supports one of the chip and the sample, vibrates with a force generated by modulating the magnetic moment of the sample with the high-frequency magnetic field of the high-frequency coil, and a detecting unit that detects the vibration of the cantilever tail I have.

The basic principle of such MRFM measurement is to modulate the frequency or intensity of a high-frequency magnetic field required for generating a magnetic resonance phenomenon by an integral multiple of the natural frequency of the cantilever, or to modulate both of these modulations. By modulating each frequency difference so as to be an integral multiple of the natural frequency of the cantilever, the magnetic moment satisfying the resonance condition in the sample (or in the resonance region) is changed with time at the modulation frequency. At this time, the time-varying magnetic moment and the magnetic field gradient generated by the magnetic chip at the position where the magnetic moment exists are represented by a 3 × 3 tensor amount. This modulation forces

(Equation 1) Is triggered. Since this force changes at the modulation frequency, it becomes the driving force that causes the cantilever to flex and vibrate at this modulation frequency. Then, by detecting the bending vibration of the cantilever, imaging of a very small region of the sample is performed using the magnetic resonance force phenomenon.

As described above, since a static magnetic field is required to generate a magnetic moment in the sample in the direction of the polarization field (magnetic polarization field), the MRFM generates a static magnetic field. Of the solenoid coil. It is also required that the MRFM be formed small and compact, so that the space for disposing the solenoid coil is limited. Therefore, it is required that a small solenoid coil for producing a desired magnetic field strength and magnetic field uniformity can be easily manufactured and can be arranged in such a limited space.

To further meet this demand, the MRFM is further examined. Since the detection sensitivity of the MRFM is extremely high, it is possible to measure a minute sample or a minute region. Therefore, high uniformity over a large space is not necessary,
If a magnetic field uniformity of about 10 ^-4 can be obtained in a space of mm ³ , it is sufficient as a static magnetic field solenoid coil used for MRFM. Therefore, the magnetic field strength required for use in the MRFM and the magnetic field uniformity of about 10 ^-4 in a space of 1 mm ³ can be respectively produced, and it can be easily manufactured and can be arranged in such a limited space. As a result of computer simulations to obtain a compact solenoid coil, even if a solenoid coil with the maximum dimensions that can be inserted into the allowable space is manufactured, the desired magnetic field strength cannot be obtained, and the magnetic field uniformity is the highest. It has been found that it is impossible at present to arrange a signal detection unit which is required in terms of size required for MRFM in the center of the solenoid type coil.

Therefore, MRFM required to be downsized
It is necessary to obtain the desired magnetic field strength and uniformity near the single solenoid coil end face, and to optimize the magnetic field strength and gradient at the sample position located near the single solenoid coil end face. There is a problem that needs to be.

Furthermore, in the conventional magnetic resonance method, a sample is set in an RF coil which is a part of a high-frequency resonator placed in a static magnetic field having high spatial uniformity as described above, and observation is performed. However, according to this conventional method, the sum of all signals of the magnetic moments of interest existing inside the sample is observed, and information on the surface microregion of the sample surface or inside the sample within a measurement depth of several 100 μm is obtained. I couldn't know. The currently developed MRFM is 1 μm
Although it is a surface analyzer having a high spatial resolution of the order, an MRFM detecting unit capable of scanning over a wide area of about several tens of cm has not been proposed at all.

Further, the high frequency necessary for the MRFM measurement is applied to the sample from a minute solenoid coil disposed near the sample, or the sample is applied directly to the sample by placing the sample on a strip line resonance circuit. . However, in this conventional method, since no heat diffusion mechanism is provided, heat generated when the irradiation power is large cannot be suppressed. For this reason, the resonance condition of the high temperature circuit part drifts, and not only does the power transfer performance deteriorate significantly, but also there is a concern about the influence of heat on the sample placed near the resonance circuit.

The present invention has been made in view of such circumstances, and an object of the present invention is to produce a desired magnetic field strength without deteriorating the spatial uniformity of a magnetic field, and to provide a solenoid coil end face. An object of the present invention is to provide a magnetic field generator having a single and small solenoid coil capable of optimizing the magnetic field strength and gradient at a nearby position. Also,
Another object of the present invention is to provide a magnetic resonance force microscope capable of obtaining sample information on a sample surface or a minute region of the sample surface and enabling a wider area scan. Another object of the present invention is to provide a magnetic resonance force microscope provided with a high-frequency coil capable of effectively dissipating heat generated by irradiating a sample with high frequency.

[0013]

According to a first aspect of the present invention, there is provided a magnetic field generating apparatus comprising: a solenoid coil for generating a static magnetic field; and a concentrically disposed solenoid coil in the solenoid coil. It is characterized by comprising at least a cylindrical high magnetic permeability magnetic body and a coil power supply for supplying a current to the solenoid coil. Further, the invention according to claim 2 is provided such that the position of the cylindrical high magnetic permeability magnetic body in the direction of the center symmetry axis of the solenoid coil can be adjusted by driving translation along the center symmetry axis of the solenoid coil. It is characterized by: Further, the invention according to claim 3 is provided with a guide means for guiding the cylindrical high magnetic permeability magnetic body in order to move the cylindrical high magnetic permeability magnetic body along a central symmetry axis of the solenoid coil. It is characterized by.

Further, in the magnetic resonance force microscope according to the present invention, a static magnetic field having a required magnetic field intensity is generated at a sample position to generate a magnetic moment in the sample in a direction of a polarized field (magnetic polarization field). A magnetic field generator according to any one of claims 1 to 3 for generating, a high frequency magnetic field applying means for applying a high frequency magnetic field to a sample, and a modulation signal for modulating the polarization field (magnetic polarization field). A modulating means for supplying to the magnetic field applying means, a magnetic field gradient generating means arranged to face the sample to generate a magnetic field gradient, and supporting one of the magnetic field gradient generating means and the sample, A vibrator that vibrates with a force generated by modulating the magnetic moment of the sample with the high-frequency magnetic field described above, and a detection unit that detects the vibration of the vibrator.

Further, according to the present invention, a fine movement drive section for moving one of the sample and the magnetic generator in a narrow scanning area, and the other of the sample and the magnetic generator in a wide scanning area. And a coarse movement drive unit for moving the first and second movements. Further, the invention according to claim 6 is characterized in that the vibrator is a cantilever, and the laser light reflected by the cantilever is introduced into the detection means through an optical fiber. Further, in the invention according to claim 7, the magnetic field applying means includes the high-frequency coil, and the high-frequency coil is thin and wide printed on a coil substrate having a low dielectric constant,
Further, the modulation means has a predetermined number of capacitors fixed to the double-sided board.

[0016]

In the magnetic field generator according to the present invention having the above-described structure, when the cylindrical high magnetic permeability magnetic body inserted into a single solenoid coil is magnetized by the solenoid coil, the cylindrical high magnetic permeability magnetic material is removed. The body creates a magnetic dipole field that depends on distance and angle. And, due to this magnetic dipole magnetic field, not only at the center position of the end face of the single solenoid coil, but also inside and outside the solenoid coil,
On the central symmetry axis of the solenoid coil, a magnetic field strength larger than the maximum magnetic field produced by the solenoid coil can be obtained without deteriorating the spatial uniformity of the magnetic field.

On the other hand, in the magnetic resonance force microscope of the present invention, a cylindrical high magnetic permeability magnetic material is inserted into a solenoid coil, and a magnetic dipole magnetic field generated by the cylindrical high magnetic permeability magnetic material is used. Thus, the magnetic field strength is increased while the magnetic field gradient is improved. As a result, the size of the solenoid coil can be reduced and the size of the coil power supply can be reduced accordingly, so that a large magnetic field generating unit such as a conventional large power supply and large solenoid is not required. Therefore, the MRFM is also small and compact.

Further, by changing the value of the current flowing through the solenoid coil, the generated magnetic field greatly changes depending on the relative magnetic permeability of the cylindrical high-permeability magnetic material. Furthermore,
The cylindrical magnetic high-permeability magnetic material translates along the central symmetry axis of the solenoid coil and adjusts its position in the center symmetry axis direction. The desired measurement depth, that is, the desired measurement depth number 100 near the surface of the magnetic chip or the sample or inside the sample.
It occurs at each position within μm.

Further, one of the detecting unit and the sample of the MRFM is set to one of the fine driving unit and the coarse driving unit, which is a piezo element, and one of the detecting unit and the sample of the MRFM is set to the fine moving unit. The drive element and the coarse drive unit are set to one of the other, so that wide-area scanning, which is impossible with the conventional MRFM in which the detection unit is fixed, can be performed. Thus, the conventional M
Imaging with a spatial resolution of several μm, which was not possible with RI technology, can be performed over a wide area.

Further, using a printed circuit board manufacturing technique,
The high-frequency coil is formed to be thin and wide on the coil substrate. As a result, the surface area of the high-frequency coil is as large as possible and the required space is small, so that the high-frequency characteristics that conduct only on the conductor surface and do not require a thick conductor are effectively utilized, and the effective high-frequency conductive area is effectively used. Is secured in a necessary minimum space. In addition, by increasing the surface area of the high-frequency coil, heat generated on the high-frequency coil generated by high-frequency irradiation is effectively radiated.

Further, by reducing the thickness of the coil substrate, the high-frequency coil can have a multilayer structure without significantly reducing the sample space between the coil substrates.
This increases the inductance of the high-frequency coil and lowers the resonance frequency band. Further, since a printed circuit board manufacturing technique is used for manufacturing a high-frequency coil, a coil with good reproducibility in shape and size can be manufactured. By using this high-frequency coil for the MRFM, it is possible to obtain an MRFM in which the high-frequency magnetic field irradiation intensity at the sample position hardly varies.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B schematically show an example of an embodiment of a magnetic field generator according to the present invention. FIG. 1A is a front view, and FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. As shown in FIG. 1, the magnetic field generator 1 of this example includes a solenoid coil 2.
Is formed by winding a conductive wire 4 around a cylindrical bobbin 3.
Although not shown, the solenoid coil 2 is fixed to a support member such as a case or a housing of the magnetic field generator 1.

A cylindrical high-permeability magnetic body 5 made of a high-permeability magnetic material which is likely to be a magnet such as pure iron, cobalt, nickel or the like is arranged on the inner peripheral side of the solenoid coil 2. The cylindrical high-permeability magnetic body 5 is axially joined to and fixed integrally to a first non-magnetic cylindrical fixing member 6, and the first non-magnetic cylindrical fixing member 6 is made of resin or the like. The inner and outer circumferences of the cylindrical high-permeability magnetic body 5 are formed in a cylindrical shape having the same size from the non-magnetic material, and a female screw 6a is formed on the inner circumferential surface.

The cylindrical high magnetic permeability magnetic body 5 and the first non-magnetic cylindrical fixing member 6 are fitted to a second non-magnetic cylindrical fixing member 7 made of a non-magnetic material having a low thermal expansion and contraction rate. And their outer peripheral surfaces are integrally fixed to the inner peripheral surface of the second non-magnetic tubular fixing member 7. Further, the second non-magnetic tubular fixing member 7 is slidably fitted on the bobbin 3 of the solenoid coil 2. In this case, a predetermined number of guide grooves 8 which are arranged in the circumferential direction and extend in the axial direction are formed on one of the outer peripheral surface of the second non-magnetic tubular fixing member 7 and the inner peripheral surface of the bobbin 3. And a guide groove 8 extending in the axial direction and slidably fitted in the guide groove 8 on one of the outer peripheral surface of the second non-magnetic cylindrical fixing member 7 and the inner peripheral surface of the bobbin 3. The same number of guide protrusions 9 are formed (in the illustrated example, guide grooves 8 are formed on the outer peripheral surface of the second non-magnetic cylindrical fixing member 7, and the guide protrusions 9 are formed on the inner peripheral surface of the bobbin 3. Is formed). The guide grooves 8 and the guide ridges 9 are fitted with high precision, so that the second non-magnetic cylindrical fixing member 7 is accurately guided relative to the bobbin 3 in the axial direction and slides. At the same time, relative rotation is prevented. Therefore, the cylindrical high-permeability magnetic body 5 and the first non-magnetic cylindrical fixing member 6 also move accurately relative to the bobbin 3 in the axial direction (vertical direction in the figure), respectively, and rotate relative to each other. Will be blocked. The guide means of the present invention is constituted by the guide groove 8 and the guide ridge 9.

A male screw 10a formed on the outer peripheral surface of the non-magnetic driving member 10 is screwed to the female screw 6a on the inner peripheral surface of the first non-magnetic cylindrical fixing member 6. The non-magnetic drive member 10 is attached to the above-described support member so that it can rotate only and cannot move in the axial direction. Therefore, by rotating the non-magnetic driving member 10, the cylindrical high-permeability magnetic body 5 is rotated.
Will slide smoothly in the axial direction. In this case, since the guide groove 8 and the guide ridge 9 are fitted, the second non-magnetic cylindrical fixing member 7 and the first non-magnetic cylindrical fixing member 8 and the cylindrical high-permeability magnetic body 5 do not rotate with the rotation of the non-magnetic driving member 10, and the rotational motion of the non-magnetic driving member 10 is converted to the linear motion of the cylindrical high-permeability magnetic body 5 with high precision. Will be done. Further, an external power supply 11 is connected to the solenoid coil 2.
Is connected, and the current from the external power supply 11 is supplied to the solenoid coil 2 so that the solenoid coil 2
Generates a magnetic field H.

In the case of the conventional magnetic field generator 1 in which a solid rod-shaped magnetic body is disposed on the inner peripheral side of the solenoid coil, as shown by a dotted line in FIG. While the strength of the magnetic field H gradually decreases as the distance increases, in the magnetic field generator 1 of this example configured as described above, the cylindrical high magnetic permeability magnetic body 5 is provided on the inner peripheral side of the solenoid coil 2. With this arrangement, a peak of the strength of the magnetic field H is generated at a desired position away from the solenoid coil 2 as indicated by a straight line in FIG. The position at which the peak of the strength of the magnetic field H is generated depends on the position in the axial direction of the cylindrical high-permeability magnetic body 5, the size of the cylindrical high-permeability magnetic body 5, and the material of the cylindrical high-permeability magnetic body 5. It will change.

When the cylindrical high-permeability magnetic material 5 is formed of an extremely high-permeability magnetic material, the magnetic field generated at a desired location is changed by the magnetic field generated by the solenoid coil 2. When the high magnetic permeability magnetic material 5 is formed of a magnetic material having a relatively low magnetic permeability among high magnetic permeability, the magnetization of the cylindrical high magnetic permeability magnetic material 5 is polarized. Further, by changing the direction of the magnetic field generated by the solenoid coil 2, the direction of the magnetic field of the cylindrical high magnetic permeability magnetic body 5 can be changed.

The principle of increasing the magnetic field strength at the center position of the coil end face and increasing the magnetic field strength by the magnetic field generator 1 of this example configured as described above will be described.
In the magnetic field generator 1 shown in FIG. 1, an electric current flows from the external coil power supply 11 to the solenoid coil 11, and a magnetic field of about several gauss: vector H is generated inside the solenoid coil 11.
Occurs. This magnetic field: The magnetic field direction of the vector H is the direction of the central symmetry axis passing through the coil center (+ z direction). Due to the magnetic field of about several gauss: vector H, magnetization of cylindrical high magnetic permeability magnetic body 5 such as pure iron: vector M = vector μ · μ
_{The zero} vector H is completely saturated. Where the vector μ
And μ ₀ are the relative magnetic permeability and the magnetic permeability in vacuum, respectively. Now, in order to consider the effect of the dipole magnetic field by the cylindrical high magnetic permeability material 5, the cylindrical high magnetic permeability material 5 is divided into small partial volume elements as shown in FIG. Let it be a vector dM. By this partial saturation magnetization: vector dM, a dipole magnetic field: vector dH _dip (vector r, θ) depending on the distance r and the angle θ is created in the periphery. At this time, in the coil center symmetry axis direction (+ z direction). Along the magnetic field strength

(Equation 2) Given by The total magnetic field strength at the center of the coil end face is
In the magnetic field generated by the solenoid coil 2 itself, the center position of the end face and the spatial positional relationship of each partial element (that is, r and θ)
Is obtained by adding the dipole magnetic fields depending on. When the magnetization of the cylindrical high-permeability magnetic material 5 is saturated, the dipole magnetic field is constant independently of the current applied to the solenoid coil 2, so that a larger current is applied to the solenoid coil 2. In this case, the dipole magnetic field is considered as an offset magnetic field, and the intensity of the surrounding magnetic field can be changed by the current applied to the coil.

A particularly important point in Equation 2 is that magic an
This means that the sign of the vector H _dip changes after gle (θ _ma {54.73}). That, H _dip is, theta becomes positive in the case of a theta _ma smaller angle, also theta is negative in case of theta _ma larger angle. By using this general and invariant physical property, by taking into account the shape and arrangement of the magnetic material, it is possible to correct the magnetic field uniformity at the coil end face position using only the solenoid coil 2, in other words, the magnetic field gradient. (B) It is possible to increase the magnetic field strength at the coil end face position.

Further, the possibility of correcting the magnetic field gradient and the possibility of increasing the magnetic field strength by the magnetic field generator 1 of this embodiment will be described in more detail by using a specific calculation example by computer simulation. First, in this calculation example, the dimensions of the solenoid coil 2 are assumed as shown in FIG. 4A, and there is no iron core in the solenoid coil 2;
Consider the case where only the coil 2 is used. Plotting three-dimensionally the magnetic field strength H _Z of the z-axis generated in the coil 2 (the central axis of symmetry of the coils) direction when current was applied to the solenoid coil 2 to 0.05 Amps (A), FIG. 4
The result is as shown in FIG. In this case, since the magnetic field strength H is axisymmetric with respect to the axis passing through the center of the coil 2, FIG.
(B) is a diagram plotting the magnetic field strength in one quadrant with respect to the central symmetry axis.

It is known that the magnetic field inside the coil 2 is proportional to the applied current. Therefore, if the maximum magnetic field intensity is normalized, the shape of the spatial distribution of the intensity is invariant to an arbitrary current value. The magnetic field strength has a general property that the spatial uniformity is good at the center of the coil, but the magnetic field strength decreases toward the end, so that the uniformity deteriorates. The position where the magnetic field intensity is strongest is in the center of the coil 2 and near the portion where the current flows. In practice,
Even if a highly conductive copper wire is used, the physical upper limit of the current value that can be applied is expected to be about 2 A / mm ^2. Therefore, the upper limit value of the magnetic field intensity that can be generated by the coil 2 shown in FIG.
240 gauss at coil center, 150 at end face center
It is about Gaussian.

When one end face of the solenoid coil 2 is set to z = 0
Magnetic field gradient along the z-axis (∂H _Z / ∂z)
When (Gauss / mm) is evaluated for the magnetic field strength shown in FIG. 4B, the result is as shown in FIG. 4C. In this case, since the magnetic field gradient is also proportional to the current value, the magnetic field gradient at the center of the coil end face becomes about 8 gauss / mm even when a current of 2 A flows.

Next, an attempt is made to increase the magnetic field strength and to improve the magnetic field gradient in the magnetic field generator using the characteristics of the magnetic dipole magnetic field of the magnetic material. In that case, FIG.
Consider a magnetic field generator 1 of the present invention in which a cylindrical high magnetic permeability magnetic body 5 is inserted into a solenoid coil 2 as shown in FIG. In this case, the shape and dimensions of the cylindrical high-permeability magnetic material 5 used in the calculation are assumed as shown in FIG. 5A, and the cylindrical high-permeability magnetic material 5 is connected to the solenoid coil as shown in FIG. 2 and concentrically. Since the assumed cylindrical high magnetic permeability magnetic body 5 is thin and the direction of the magnetic field is the same as the axial direction of the cylindrical high magnetic permeability magnetic body 5, the demagnetizing field coefficient is expected to be small. Therefore, the effect of the demagnetizing field was ignored in the calculation. Further, in the magnetic field generator 1, the first and second non-magnetic tubular fixing members 6,
7 and the non-magnetic driving member 10 are of course
Since it is 1, the influence on the magnetic field strength at each spatial position is negligible, and pure iron is assumed for the magnetic material 5 and its relative magnetic permeability is 5000 or more.

Therefore, the magnetic field of several gauss generated inside the coil 2 by the applied current of 0.05 A completely saturates the magnetization of the pure iron, and the magnetic flux density B inside the pure iron becomes about 1
It will be 5.5k0e. The magnetized magnetic material is divided into small partial volume elements, and the dipole magnetic field at each spatial position by each element is calculated. By adding them all, the total magnetic field in the region near the end face shown in gray in FIG. 5A was evaluated. The resulting magnetic field distribution is shown in FIGS. 5 (b) and (c). FIG.
The magnetic field distribution shown in (b) is a case where the current applied to the solenoid coil 2 is 0.05 A, and the magnetic field strength and the magnetic field gradient at the center position (0, 0) of the coil end face are respectively 20.
5 gauss and +3 gauss / mm.
The magnetic field distribution shown in (c) is a case where the current applied to the solenoid coil 2 is 2 A, and the coil end surface center position (0,
The field strength and field gradient at 0) were 346 gauss and -5 gauss / mm, respectively. From these results, it was found that by using the cylindrical high-permeability magnetic material 5, it is possible to increase the magnetic field strength while improving the magnetic field gradient.

A cylindrical high-permeability magnetic material 5 made of pure iron
5A is located concentrically further toward the inside of the coil (upward in the figure) by about 1 cm along the z-axis from the position shown in FIG. FIG. 6A shows the same magnetic field intensity distribution as in FIG.
As is clear from FIG. 6A, the dipole magnetic field generated by the pure iron cylindrical high magnetic permeability magnetic body 5 causes the coil center symmetry axis (z
The structure has a peak on the (axis), and at this peak position, the magnetic field gradient is zero. Accordingly, by moving the cylindrical high magnetic permeability magnetic body 5 along the coil center symmetry axis (z axis) while maintaining concentricity with the solenoid coil 2, a peak position having a required magnetic field strength and a magnetic field gradient is obtained. Was found to be configurable where required.

Therefore, one of the guide grooves 8, the bobbin 3 and the female screw 6 a of the first non-magnetic cylindrical fixing member 6, the bobbin 3 and the second non-magnetic cylindrical fixing member 7 as shown in FIG. The other non-magnetic tubular fixing member 7 has one of the other guide protrusions 9 and the male screw 10 of the non-magnetic driving member 10.
By moving the cylindrical high-permeability magnetic body 5 along the axis of symmetry of the coil (z-axis) while maintaining concentricity with the solenoid coil 2 by using the guide and the driving means consisting of a. The peak position having the magnetic field gradient can be adjusted to a desired position. As a driving means for moving the cylindrical high magnetic permeability magnetic body 5, the cylindrical high magnetic permeability magnetic body 5 is moved along the coil center symmetry axis (z axis) while maintaining concentricity with the solenoid coil 2. If possible, other guides and drive means such as guide means comprising a slide rail and drive means comprising a worm gear and a rack gear can be used.

On the other hand, the shape of the solenoid coil 2 may be virtually any length and thickness. The important point is the magnetic permeability, shape and arrangement of the magnetic material on the magnetic body side, that is, it is important that the magnetic body has a high magnetic permeability and is formed in a cylindrical shape, and it is important to arrange it concentrically with the solenoid coil. It is. Therefore, due to the characteristics near the magic angle of the magnetic dipole magnetic field, even if a single rod-shaped magnetic body is inserted into the solenoid coil, the effect of increasing the magnetic field strength is obtained, but the effect of reducing the magnetic field gradient is obtained. Absent.

In the example described above, it was assumed that the magnetic material had a very high magnetic permeability and therefore its magnetization was saturated. Thus, the magnetic material produces a constant magnetic field strength and gradient (or zero gradient at the center of the coil end face), where the coil end face position is governed by the magnetic field strength and field gradient created by the coil itself, which varies with the applied current value. . On the other hand, if a material with low magnetic permeability that does not saturate the magnetization of the material is used, the magnetic field strength obtained at the coil end face position will decrease, but the variable range of the strength can be expanded without greatly changing the magnetic field gradient. Can also.

For example, a cylindrical high-permeability magnetic material 5 is shown in FIG.
Assuming the same structure and dimensions as shown in
FIGS. 6 (b) and 6 (c) show the results in the case where a magnetic material having a relative magnetic permeability of 10 is used and the current applied to the solenoid coil 2 is set to 0.05 A and 2 A, respectively.
Shown in Further, the cylindrical high magnetic permeability magnetic body 5 is similarly
Assuming the same structure and the same dimensions as those shown in (a), it is formed of a magnetic material having a relative magnetic permeability of 30,
The applied current to the solenoid coil 2 is 0.05 A
6 (d) and (e) show the results when the values are set to 2A and 2A. As is apparent from FIGS. 6B to 6E, the magnetic field gradient at the center of the coil end face is worse than the magnetic field gradient obtained when the magnetization is saturated, but the shape and position of the magnetic material are changed. The first condition can be obtained by adjusting.

Thus, the magnetic field generator 1 of this example
According to (1), a cylindrical high-permeability magnetic body 5 having a high magnetic permeability is inserted into a single solenoid coil 2 and is made of a cylindrical high-permeability magnetic body 5 magnetized by the solenoid coil 2. By utilizing the effect of the magnetic dipole magnetic field, which depends on distance and angle, the coil is created by the coil not only at the center position of the end face of the single coil, but also on the center symmetry axis of the coil, both inside and outside the coil The effect that a magnetic field strength larger than the maximum magnetic field can be obtained without impairing the spatial uniformity of the magnetic field can be obtained.

Next, an example of an embodiment of a magnetic resonance force microscope according to the present invention using the magnetic field generator 1 will be described. FIG. 7 is a perspective view schematically showing the MRFM of this example. FIG. 8 is a perspective view of the MRFM of this example.
0 and the capacitors in the capacitor storage unit 21 of the RF resonance circuit are shown in more detail and schematically, wherein (a) is a front view and (b) is a bottom view. As shown in FIG.
The MRFM 12 of this example includes the magnetic field generator 1 described above. The solenoid coil 2 of the magnetic field generator 1 is formed as a small solenoid, and the upper end thereof is fixed to the lower end of a piezo element 14 via a spacer 13. The upper end of the piezo element 14 is fixed to the apparatus main body 15 of the MRFM 12. The piezo element 14 constitutes a fine movement driving element for performing narrow-area scanning. Further, the solenoid coil 2 is connected to a coil power supply 11.

A cantilever support member 16 is fixed to the lower end of the solenoid coil 2, and a flexible cantilever 18 (the present invention) is attached to the cantilever support member 16 via a piezo element 17 for vibrating the cantilever. ) Is cantilevered. The cantilever oscillating piezoelectric element 17 can forcibly vibrate the cantilever 18. The free end of the cantilever 18 extends beyond the central symmetry axis of the solenoid coil 2, and a magnetic chip 19 (corresponding to the magnetic field gradient generating means of the present invention) is provided at the center of the free end of the solenoid coil 2. Installed. The magnetic tip 19 generates a magnetic field gradient, and bends the cantilever 18 by a magnetic resonance force generated by the interaction with the sample through the magnetic field gradient.

Further, an RF coil 20, which is a high frequency coil for magnetic resonance, is provided near the free end of the cantilever 18, and this RF coil 20 is connected to a capacitor storage section 21 of the RF resonance circuit. . The capacitor storage section 21 of the RF resonance circuit is provided in an RF coil support member 22 fixed to a lower end of the solenoid coil 2. In that case, the capacitor storage section 21 of the RF resonance circuit is provided so that the RF magnetic field generated by the RF coil is perpendicular to the direction of the effective static magnetic field. In addition,
The capacitor storage section 21 of the RF resonance circuit can be provided outside the RF coil support member 22. The capacitor storage section 21 of this RF resonance circuit is connected to the R
It is connected to the F power supply 24.

As shown in FIGS. 8A and 8B, the capacitor housing 21 has a double-sided board 27 grounded to the ground. Are securely fixed by soldering, and a second trimmer capacitor 29 smaller than the first trimmer capacitor 28 is provided. A third trimmer capacitor 30 is similarly firmly fixed to the other surface of the double-sided board 27 by soldering. The first and third trimmer capacitors 28 and 30 constitute a main capacitor in the capacitor storage unit 21. Since these capacitors 28, 29, and 30 are all variable capacitors, they need to be adjusted by a driver or the like. Therefore, the first and third capacitors 28, 30 are arranged relatively shifted left and right or up and down.

On the other hand, the RF coil 20 which is a high-frequency coil
Is formed by a pair of thin and wide annular high-frequency coils 20a and 20b formed on a pair of coil substrates 31 and 32, respectively, as a single-layer coil using printed circuit board technology. The pair of high-frequency coils 20a and 20b are connected to each other. The pair of coil substrates 31 and 32 are formed of a material having a low dielectric constant such as sapphire or silicon single crystal and having a high thermal conductivity and a good heat dissipation property.
Circular holes 34 and 35 are formed in the 1 and 32 high-frequency coil 20a and 20b manufacturing portions concentrically with the high-frequency coils 20a and 20b, respectively. The position of the sample 39 obtained can be confirmed. Furthermore, a pair of coil substrates 3
The reference numerals 1 and 32 are arranged such that one end side of the double-sided board 27 is sandwiched between the two end faces of the double-sided board 27, and are firmly fixed with a non-magnetic adhesive or a plastic screw. In that case, a sample space 33 into which the sample 39 can enter is formed between the pair of coil substrates 31 and 32.

Further, the high-frequency coil 20a formed on one of the coil substrates 31 has a small second trimmer capacitor 2a.
9 and a small second trimmer capacitor 29 is connected by a wire to the first trimmer capacitor 28 at the shortest distance. The high-frequency coil 20b formed on the other coil substrate 32 is similarly connected to a third trimmer capacitor 30 as a main capacitor by a wire. Further, the first trimmer capacitor 2
Reference numeral 8 denotes an RF power source 2 that emits high frequency through a coaxial cable 23.
4 is connected. The RF coil 20 applies a high-frequency magnetic field to the sample 39 set in the sample space 33 by a current from a capacitor in the capacitor storage unit 21.

In the RF coil 20 shown in FIG. 8, the pair of high-frequency coils 20a and 20b are formed in a single layer on the pair of coil substrates 31 and 32, respectively, but as shown in FIG. , 32 are reduced in thickness to form two thin substrates 31a, 31b;
2b are laminated, and the thin substrates 3
1a, 31b; 32a, on the 32 b, 3 sheets of the high-frequency coil 20a respectively _{1, 20a 2, 20a 3;} 20b 1, 20b 2, 2
The provided 0b _3, without reducing the sample space 33,
The RF coil 20 may be configured in a laminated structure. In this way, a large magnetic field strength can be obtained without increasing the size of the RF coil 20. The high-frequency coils 2 are provided on the single-layer coil substrates 31 and 32, respectively.
0a and 20b may be laminated.

The connection between each capacitor and the connection between the capacitor and the RF coil in the high-frequency circuit are made by wires as shown in FIG. 8 and by the substrates 27, 31 and 32 as shown in FIG. You can do it too. FIG. 11 shows an equivalent circuit of this high-frequency circuit. In this case, the RF coil 20 shown by a dotted line in FIG.
The capacitor 36 provided in parallel with the third capacitor 30 is an additional floating capacitance formed between the double-sided board 27 and the coil board 31 shown in FIG. Since this additional stray capacitance must be minimized, care must be taken in the arrangement of the substrate so that sufficient irradiation power is applied to the sample 39.

Further, an optical fiber 25 extends through the solenoid coil 2 and the cylindrical high-permeability magnetic body 5 along the axis of symmetry of the center of the solenoid coil 2. One end of the optical fiber 25 faces the free end of the cantilever 18, the other end of the optical fiber 25 extends outside from the spacer 13, and the other end is connected to the optical interference detector 26. ing. The sample 39 set in a static magnetic field, which is a magnetic dipole magnetic field generated by the magnetic field generator 1, is irradiated with a high-frequency magnetic field modulated by the RF coil 20 at an integral multiple of the natural frequency of the cantilever. Then, a magnetic resonance phenomenon occurs, and the magnetic moment in the sample 39 changes with time at the modulation frequency through the magnetic resonance phenomenon. The interaction between the magnetic moment changing with the modulation frequency and the magnetic field gradient generated by the magnetic chip 17 generates a time-changing force with the modulation frequency, and this force causes the cantilever 18 to bend and vibrate. Let it. The optical fiber 25 transmits the laser light output from the optical interference detector 26 to the cantilever 18.
And irradiates the free end of the cantilever 18, and guides the MRFM signal appearing as the bending vibration of the cantilever 18 to the optical interference detector 26 as laser light reflected by the cantilever 18. The optical interference detector 26 detects the laser light passing through the optical fiber 25 by an optical interference method.

In the MRFM 12 of this embodiment, the small solenoid coil 2, the cylindrical high-permeability magnetic body 5, and the non-magnetic drive member for moving the cylindrical high-permeability magnetic body 5 along the axially symmetric axis of the solenoid coil 2. According to 10, MRFM
A portion that generates a static magnetic field necessary for the magnetic resonance measurement is configured. In this case, the role of the cylindrical high-permeability magnetic body 5 is to generate a large magnetic field strength that cannot be generated by the small solenoid coil 2 alone, as described above. By using a dipole magnetic field to generate a magnetic field with good spatial uniformity at a required position, that is, at a position in the vicinity of the surface of the magnetic chip 19 or the sample 39 or within a desired measurement depth of several 100 μm inside the sample 39, In addition, the role of the non-magnetic driving member 10 is to generate a large magnetic field strength at a position which cannot be generated by the small solenoid coil 2 alone. A cylindrical high-permeability magnetic material 5 is translated along a central symmetry axis of the solenoid coil 2.
Adjusting the position of the solenoid coil 2 in the central symmetric axis direction. FIGS. 7 and 8 do not show the non-magnetic driving member 10 that translates the cylindrical high-permeability magnetic body 5 along the central symmetry axis of the solenoid coil 2. Also, a magnetic tip 19 for generating a magnetic field gradient at the free end of the cantilever 18, the cantilever 18, the cantilever support member 16, and the piezo element 1 for cantilever excitation.
7, a part for detecting an MRFM signal is formed. Further, an RF resonance circuit including an RF coil 20 and a capacitor stored in a capacitor storage unit 21 irradiates an RF magnetic field to the sample surface with a high frequency for magnetic resonance. Is generated. By these parts, MRF
The detection unit of M12 is configured.

On the other hand, in the example shown in FIG.
A sample table 38 is fixed to the apparatus main body 15 via a coarse movement driving section 37 composed of a piezo element, and a sample 39 to be measured is set on the sample table 38. Then, the wide area scanning of the sample 39 is performed by moving the coarse movement driving unit 37,
9 is performed by driving with the piezo element 14 of the detection unit.

In the MRFM 12 of this example, the sample space 33 is narrow, and the sample 39 is inserted into this narrow space. Magnetic resonance signals of electron spins or nuclear spins existing in the range of about 100 μm
It can be measured as an M image.

The thus configured MRFM1 of this example
According to (2), (1) the cylindrical high magnetic permeability magnetic material 5 is inserted into the solenoid coil 2 and the magnetic dipole magnetic field generated by the cylindrical high magnetic permeability magnetic material 5 is used. And the magnetic field strength can be increased. Accordingly, the size of the solenoid coil 2 can be reduced and the size of the coil power supply 11 can be reduced accordingly, so that a large magnetic field generating unit such as a conventional large power supply and large solenoid coil can be eliminated. Therefore, the MRFM 12 can also be made compact and compact. (2) It is possible to greatly change the generated magnetic field depending on the relative permeability of the cylindrical high-permeability magnetic body 5 by changing the value of the current flowing through the solenoid coil 2. Become,

(3) Since the cylindrical high-permeability magnetic body 5 is translated along the center symmetric axis direction of the solenoid coil 2 to adjust the position of the center symmetric axis direction, the generated magnetic field is limited to the space. (4) MRF that can generate a static magnetic field with extremely good uniformity at a position where a magnetic field is required, that is, at a position near the surface of the magnetic chip 19 or the sample 39 or within a desired measurement depth of several 100 μm inside the sample 39.
Since the cantilever 18, the RF coil 20, and the laser beam irradiating unit used for the M12 detection unit are arranged at the center of the end surface of the solenoid coil 2 on the sample 39 side, respectively.
The measurement by the MRFM 12 becomes possible. This enables imaging with a spatial resolution of several μm.

(5) Using a printed circuit board manufacturing technique, R
Since the F coil 20 is formed of a thin and wide high-frequency coil on the coil substrates 31 and 32, and the surface area of the RF coil 20 is as large as possible and the necessary space is small,
The property of the high-frequency magnetic field, which conducts only on the conductor surface and does not require a thick conductor, can be effectively utilized, and the effective effective conduction area of the high-frequency magnetic field can be secured in the minimum necessary space. (6) R
By increasing the surface area of the F coil 20, heat generated on the coil caused by irradiation of a high-frequency magnetic field can be effectively dissipated. (7) By reducing the thickness of the coil substrates 31, 32, the coil Sample space 3 between substrates 31 and 32
3, the RF coil 20 can have a multi-layer structure without significantly reducing the magnetic field strength.

(8) Further, by forming the RF coil 20 with a multilayer structure, the inductance of the RF coil 20 can be further increased and the resonance frequency band can be lowered. (9) The dielectric constant of the coil substrates 31 and 32 can be reduced. Since a low insulator is used, it is possible to prevent the high-frequency characteristics and supply power characteristics at the sample position from being significantly impaired.
Since a material having good heat conductivity is used for the heat sink 32, heat generated in the RF coil 20 can be more effectively released.
(11) Since the printed circuit board manufacturing technology is used for manufacturing the RF coil 20, a coil having good reproducibility in shape and size can be manufactured.
With the use of the MFM 12, it is possible to obtain the MRFM 12 having almost no variation in the high-frequency magnetic field irradiation intensity at the sample position.

(12) The two main capacitors 2 are symmetrical with respect to the double-sided board 27 grounded to the ground.
8 and 30, the stray capacitance due to wires and the like necessary for connection is suppressed as much as possible, and the capacitors 28 and 3 are connected in the shortest distance.
0 and the RF coil 20, the ground plane can be secured in a wide area, and the high-frequency resonance circuit can be stabilized. (13) As shown in FIG. By connecting the coil 20 with a substrate, a firm coupling installation surface required for a high-frequency circuit can be obtained, and in the case of a wire, the variation in the frequency characteristics of the resonance circuit caused by the arbitrary position of the wire is suppressed. Can be obtained.

In the above-described example, the detection section of the MRFM 12 is attached to the piezo element 14 for narrow-area scanning, and the sample 39 is set on the coarse movement driving section 37. Piezo element 14 for narrow area scanning
And the detection unit of the MRFM 12 is set to the coarse movement driving unit 3.
7 can also be set. Furthermore, in FIG. 7, the top and bottom (up and down) can be configured to be completely reversed.

FIG. 12 is a perspective view schematically showing another embodiment of the magnetic resonance force microscope according to the present invention, and FIG.
FIG. 13 is a diagram schematically showing details in the vicinity of a solenoid coil of the example shown in FIG. 12. Note that the same reference numerals are given to components corresponding to those in the above-described example, and a detailed description thereof will be omitted. In the above-described example, since the printed circuit board RF circuit is used, the sample space 33 between the two substrates 31 and 32 is relatively narrow, so that the scan area of the sample is limited to a narrow range, and wide area scan is impossible. There is a MRFM12 in this example
Does not use the printed circuit board RF circuit, but uses a conventional RF coil 20 made of a normal wire as the RF coil 20 as shown in FIGS. M in this example
The other configuration of the RFM 12 is substantially the same as the above-described example.

The thus configured MRFM1 of this example
In 2, one of the detection unit and the sample of the MRFM 12 is set to one of the fine movement drive element including the piezo element 14 and the coarse movement drive unit 37, and the MRFM
12 is set on one of the other of the fine drive element and the coarse drive section 37, and the cantilever 18 of the detection section of the MRFM 12 is set.
Since there is no obstacle such as a printed circuit board as in the above example around the MRF, the MRF to which the detection unit is fixed as in the related art is used.
A wide area scan of the sample 39, which was impossible with M, can be performed. Therefore, in the MRFM 12 of this example, 1 to Expression 1
With respect to the sample 39 having a surface of about 0 cm, a magnetic resonance signal of an electron spin or a nuclear spin existing in a range of about 100 μm in depth over the entire surface can be measured as an MRFM image.

The thus configured MRFM1 of this example
According to (2), either (14) one of the detection unit and the sample of the MRFM 12 is set to one of the fine drive unit and the coarse drive unit 37 composed of the piezo element 14, and
Since the other of the detection unit and the sample of the FM 12 is set to the other of the fine movement drive element and the coarse movement drive unit 37, the MRFM in which the detection unit is fixed as in the related art is used.
(15) There is an effect that imaging with a spatial resolution of several μm, which is impossible with the conventional MRI technology, is possible over a wide area. Other functions and effects of the MRFM 12 of this example are the same as the functions and effects of the above-described example except for the functions and effects of the printed circuit board.

Also in this example, the detection unit of the MRFM 12 is attached to the piezo element 14 for narrow-area scanning,
Also, the sample 39 is set in the coarse movement drive unit 37. Conversely, the sample 39 is set in the piezo element 14 for narrow area scanning, and the detection unit of the MRFM 12 is set in the coarse movement drive unit 37. Alternatively, the top and bottom (up and down) in FIG. 12 can be completely reversed. The magnetic field generator 1 of the present invention can be applied to any device other than the MRFM, as long as the device requires a high magnetic field strength and a high magnetic field uniformity.

[0063]

As is apparent from the above description, according to the magnetic field generator of the first aspect of the present invention, a magnetic dipole magnetic field is generated by a cylindrical high magnetic permeability magnetic body inserted in a single solenoid coil. Due to this magnetic dipole magnetic field, not only at the center position of the end face of the single solenoid coil, but also inside and outside of the solenoid coil, it is formed by the solenoid coil on the central symmetry axis of the solenoid coil. A magnetic field strength greater than the maximum magnetic field,
It can be obtained without impairing the spatial uniformity of the magnetic field.

On the other hand, according to the magnetic resonance force microscope of the present invention, a cylindrical high magnetic permeability magnetic material is inserted into a solenoid coil, and a magnetic dipole magnetic field generated by the cylindrical high magnetic permeability magnetic material is used. Therefore, the magnetic field strength can be increased while improving the magnetic field gradient. As a result, the size of the solenoid coil can be reduced and the size of the coil power supply can be reduced, so that a large magnetic field generating unit such as a conventional large power supply and a large solenoid is not required.
RFMs can also be small and compact.

Further, by changing the value of the current flowing through the solenoid coil, it is possible to greatly change the generated magnetic field depending on the relative magnetic permeability of the cylindrical high-permeability magnetic material.
Furthermore, by moving the cylindrical high magnetic permeability magnetic body along the center symmetry axis direction of the solenoid coil and adjusting the position of the center symmetry axis direction, the generated magnetic field can be converted to a static magnetic field with extremely excellent spatial uniformity. It can be generated at a required position, that is, at a position in the vicinity of the surface of the magnetic chip or the sample or within a desired measurement depth of several hundred μm inside the sample.

Further, either one of the detecting section of the MRFM and the sample is set on one of the fine driving element and the coarse driving section made of a piezo element, and one of the detecting section of the MRFM and the other sample is set on the fine moving section. Since it is set to one of the drive element and the coarse drive unit, it is possible to perform a wide area scan which was impossible in the conventional MRFM in which the detection unit is fixed. In this way, imaging with a spatial resolution of several μm, which was impossible with the conventional MRI technology, can be performed over a wide area.

Further, using a printed circuit board manufacturing technique,
Since the high-frequency coil is formed thin and wide on the coil substrate, the surface area of the high-frequency coil can be made as large as possible and the required space can be made small. This allows
A high-frequency characteristic that does not require a thick conductor that conducts only on the conductor surface can be effectively utilized, and a substantially effective high-frequency conduction region can be secured in a necessary minimum space. In addition, by increasing the surface area of the high-frequency coil, heat generated on the high-frequency coil caused by high-frequency irradiation can be effectively dissipated.

Further, by reducing the thickness of the coil substrate, the high-frequency coil can have a multilayer structure without significantly reducing the sample space between the coil substrates.
This can increase the inductance of the high frequency coil,
The resonance frequency band can be lowered. Further, since a printed circuit board manufacturing technique is used for manufacturing the high-frequency coil, a coil with good reproducibility in shape and size can be manufactured. Then, by using this high-frequency coil for MRFM, it is possible to obtain an MRFM in which the irradiation intensity of the high-frequency magnetic field at the sample position hardly varies.

[Brief description of the drawings]

FIG. 1 schematically shows an example of an embodiment of a magnetic field generator according to the present invention, wherein (a) is a front view and (b) is (a).
FIG. 3 is a cross-sectional view taken along the line IB-IB in FIG.

FIG. 2 is a diagram showing a magnetic field with respect to a distance from a center position of an end surface of a solenoid coil.

FIG. 3 is a diagram illustrating a dipole magnetic field produced by a cylindrical high-permeability magnetic body 5;

4A and 4B show a specific example of calculation by a computer simulation of a magnetic field generated by a solenoid coil in which no magnetic substance is provided therein, and FIG. 4A is a diagram showing dimensions of the solenoid coil used in this specific calculation; ) Is the magnetic field intensity H _{Z in the} z-axis (central symmetry axis of the coil) generated in the coil when a current of 0.05 A is applied to the solenoid coil.
(C) shows a magnetic field gradient (ΔH _Z / Δz) (Gauss / mm) along the z-axis when one end face of the solenoid coil is set to z = 0. FIG. 4 (b)
FIG. 4 is a diagram showing an evaluation of the magnetic field strength shown in FIG.

FIG. 5 shows a specific example of calculation by computer simulation of a magnetic field generated by a solenoid coil in which a cylindrical high-permeability magnetic body is disposed. FIG. 5 (a) shows a solenoid coil and a cylinder used in this specific calculation. FIG. 3B shows the dimensions of the magnetic material having a high permeability, and FIG.
FIG. 3C is a diagram in which a magnetic field distribution when a current of A is applied is three-dimensionally plotted, and FIG. 3C is a diagram in which a magnetic field distribution when a current of 2 A is applied to the solenoid coil is three-dimensionally plotted.

FIG. 6 shows a cylindrical high-permeability magnetic material made of pure iron.
(A) A specific example of a magnetic field generated by a solenoid coil and a cylindrical high-permeability magnetic material in a state of being concentrically located about 1 cm further inside the coil along the z-axis from the position shown in FIG. FIG. 5A shows a magnetic field intensity distribution when a current of 2 A flows through the solenoid coil, and FIGS. 5B and 5C show cylindrical high-permeability magnetic materials, respectively, in FIG. 5A. Assuming that they have the same structure and the same dimensions as those of the above, they are formed of a magnetic material having a relative magnetic permeability of 10, and the applied current to the solenoid coil is 0.05.
FIG. 7 is a diagram showing a magnetic field intensity distribution when set to A and 2A;
(D) and (e) assume that the cylindrical high-permeability magnetic material has the same structure and the same dimensions as those shown in FIG. 5 (a), and is formed of a magnetic material having a relative magnetic permeability of 30. FIG. 5 is a diagram showing a magnetic field intensity distribution when the current applied to the solenoid coil is set to 0.05 A and 2 A.

FIG. 7 is a perspective view schematically showing an example of an embodiment of a magnetic resonance force microscope according to the present invention.

FIGS. 8A and 8B show the high-frequency coil and the capacitor of the high-frequency resonance circuit of the magnetic resonance force microscope in FIG. 7 in more detail and schematically, wherein FIG. 8A is a front view and FIG.

FIG. 9 is a diagram showing a modification of the high-frequency coil.

FIG. 10 is a diagram showing a modification of the connection between the high-frequency coil and the capacitor.

11 is a diagram showing an equivalent circuit of the connection between the high-frequency coil and the capacitor shown in FIG.

FIG. 12 is a perspective view schematically showing another example of the embodiment of the magnetic resonance force microscope according to the present invention.

13 is a diagram schematically showing details in the vicinity of a solenoid coil of the example shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic field generation device, 2 ... Solenoid coil, 5 ... Cylindrical high magnetic permeability magnetic body, 6 ... 1st non-magnetic cylindrical fixing member, 6a ...
Female screw, 7: second non-magnetic cylindrical fixing member, 8: guide groove, 9: guide ridge, 10: non-magnetic driving member, 10a ...
Male screw, 11: coil power supply, 12: magnetic resonance force microscope (MRFM), 14: piezo element, 15: MRFM12
Of the apparatus, 17: Piezo element for cantilever vibration, 1
8: cantilever, 19: magnetic chip, 20: RF coil (high frequency coil), 21: capacitor storage part of RF resonance circuit, 23: coaxial cable, 24: RF power supply, 25 ...
Optical fiber, 26: Optical interference detector, 27: Double-sided board, 2
8: first trimmer capacitor, 29: second trimmer capacitor, 30: third trimmer capacitor, 31, 32: coil substrate, 33: sample space, 37: coarse drive unit, 38: sample stage, 39: sample

Claims (7)

[Claims] A solenoid coil for generating a static magnetic field;
A magnetic field generator comprising at least a cylindrical high-permeability magnetic material concentrically disposed in the solenoid coil and a coil power supply for supplying a current to the solenoid coil. 2. The method according to claim 1, wherein the cylindrical high-permeability magnetic body is provided so as to be capable of adjusting the position of the solenoid coil in the direction of the center symmetry axis by driving translation along the center symmetry axis of the solenoid coil. The magnetic field generation device according to claim 1. 3. A guide means for guiding the cylindrical high magnetic permeability magnetic body to move the cylindrical high magnetic permeability magnetic body along an axis of central symmetry of the solenoid coil. The magnetic field generator according to claim 2. 4. The method according to claim 1, wherein a static magnetic field having a required magnetic field intensity is generated at a sample position to generate a magnetic moment in the sample in a direction of a polarized field (magnetic polarization field). A high-frequency magnetic field applying means for applying a high-frequency magnetic field to the sample; a modulation means for supplying a modulation signal for modulating the polarization field (magnetic polarization field) to the high-frequency magnetic field applying means; A magnetic field gradient generating means for generating a magnetic field gradient which is arranged opposite to the magnetic field generating means, and supporting either one of the magnetic field gradient generating means and the sample, and modulating a magnetic moment of the sample by a high frequency magnetic field of the high frequency magnetic field applying means. A magnetic resonance force microscope comprising at least a vibrator vibrating with the force generated in step (a) and a detecting means for detecting the vibration of the vibrator. 5. A fine drive for moving one of the sample and the magnetic generator in a narrow scan area, and a coarse drive for moving the other of the sample and the magnetic generator in a wide scan area. The magnetic resonance force microscope according to claim 4, comprising: 6. The magnetic resonance apparatus according to claim 4, wherein the vibrator is a cantilever, and a laser beam reflected by the cantilever is introduced into the detection means through an optical fiber. Force microscope. 7. The magnetic field applying means includes the high-frequency coil, and the high-frequency coil is printed thin and wide on a coil substrate having a low dielectric constant, and the modulation means is fixed to a double-sided substrate. 7. A method according to claim 4, wherein said capacitor has a predetermined number of capacitors.
A magnetic resonance force microscope as described.