JPS6017370A - Magnetic resonance apparatus - Google Patents

Abstract

PURPOSE:To furthermore improve a signal-noise ratio and to make a local excitation possible by fitting a dielectric body electromagnetic lens of single or biconvex lens shape, in which the refracting surface is such as rotating hyperboloid, into at least one opening part of electromagnetic horns. CONSTITUTION:A pair of electromagnetic horns 13, 18 for transmission and reception are provided, a microwave supplied through a circulator 39 is outputted from the transmitting horn 13 and is received by the receiving horn 18, sent to a magic T circuit 41, and the microwave absorption is detected. Electromagnetic lenses are attached directly at the opening parts of the horns 13 and 18. The microwave emitted from the transmitting horn is propagated while spreading into air usually as a spherical wave. Since the spherical wave becomes a plane wave by using the electromagnetic lens, and the spatial spreading becomes constant, the microwave leakage is eliminated, the microwave can be irradiated effectively to a sample mounted between the horns, and the detecting sensitivity is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron spin magnetic resonance or ferromagnetic (including ferrimagnetic) resonance device using microwaves, and more specifically, to an electron spin magnetic resonance or ferromagnetic (including ferrimagnetic) resonance device using microwaves. This article relates to magnetic resonance measurement equipment.

An electron spin magnetic resonance apparatus (hereinafter referred to as an ESR apparatus) is also called a ferromagnetic resonance apparatus (hereinafter referred to as an FME apparatus) when the target substance to be measured is a ferromagnetic substance or a different magnetic substance. This device is widely used as a spectroscopic method to investigate the magnetic properties of paramagnetic ions, paramagnetic substances, radicals, ferromagnetic substances, and magnetic substances (e.g., garnet thin films for magnetic bubble devices). , it is now possible to obtain commercially available equipment.

Conventional devices commonly use cavity resonators. That is, the measurement sample is mounted on a sample holder made of a material with relatively low dielectric loss against microwaves, such as a quartz tube, quartz rod, Teflon tube, or Teflon rod, and placed inside a cavity resonator to measure ESB or FMR. There is. In this method, (1) the sample is inserted into the cavity, which limits the size of the sample; (2) the sample may significantly reduce the Q value of the lI dielectric loss cavity resonator; From too.

Sample volume (#area for membrane samples) is restricted (3)
This method has problems and drawbacks, such as the need to prepare small sample pieces by destroying large-area samples. or,
Similarly, in the method using a cavity resonator, a hole with a diameter of several tm is made in one or several places in the cavity resonator, and the BSR and FMR are measured using the microwaves leaking from the cavity resonator. For example, methods are described in Applied Physics (Matar, Res, Eu11.), Vol. 12, p. 53 (1977).
Appl, Phys,) Volume 12, page 261 (197
7 years), or the collection of summaries of the 21st PXsa debate (
1'982 (October 1982), page 134, etc. These methods of measuring magnetic resonance by drilling a hole in a cavity resonator have poor sensitivity because they use only a small portion of the power of the microwaves used, and they also Since the sample holder must be provided in a narrow space between the pole piece surface and the pole piece surface, there are still restrictions such as difficulties in jig design. In both the method of inserting the sample into the cavity resonator and the method of pressing the sample into a hole drilled in the cavity,61 both require the provision of a mechanical part that applies stress to the sample. Space constraints were a major drawback. Cavity resonators generally have a high Q value and high sensitivity, but one of their drawbacks is that it takes time to adjust the phase and frequency of microwaves. Also, the cavity resonator has a natural frequency (fo)
Since it is a resonant circuit with , the fAI+8 wave number is fixed to this fO. Therefore, the inability to freely measure the frequency dependence of the sample is also a major drawback.

In order to overcome the drawbacks of the E8 FMR device using a cavity resonator, the present inventors filed a patent application filed in 1983-215.
As described in detail in Section 075, a magnetic resonance apparatus has already been proposed which includes a transmitting electromagnetic horn, a receiving electromagnetic horn, and a sample holding section for holding a sample between the two electromagnetic horns.

The present invention improves the performance of such an electromagnetic horn type magnetic resonance apparatus.
It is an object of the present invention to provide a magnetic resonance apparatus equipped with an electromagnetic lens that can further improve the (signal-to-noise ratio), concentrate microwaves on a part of the sample, locally excite it, and change the measurement location.

That is, the present invention provides a magnetic resonance apparatus having a transmitting electromagnetic horn and a receiving electromagnetic horn with a sample holder that holds a lζ sample between these two electromagnetic horns. A dielectric electromagnetic lens in the form of a lens or a biconvex lens is fitted into the opening of at least one of the two electromagnetic horns.
This is a magnetic resonance device with the following characteristics. .

The configuration of the present invention will be explained in more detail below. 1st
The figure is an example of a specific example constituting the present invention. 11 is
This is a coaxial cable for carrying microwaves, and microwaves having a specific frequency are supplied from a circuit system 1 collectively called a microwave unit. 12 is a coaxial waveguide converter, and 13 is a transmission pawn.

14 and 15 are electromagnetic lenses that are a feature of the present invention.

16 is a sample boulder, on which a measurement sample 17 is held. The sample may be a solid, a liquid placed in a cell, a gas placed in a cell, etc. Reference numeral 18 denotes a receiving horn, which is sent to a coaxial cable via a waveguide converter 19, and absorption of the microwave by the sample 17 is detected by a microwave detection system. The electromagnetic horns for transmitting and receiving are both mounted on the rail 21, and the distance between the horns can be adjusted. 22
is an electromagnet, and the wings are pole pieces. Coaxial cable 11
, instead of using a coaxial waveguide 12, the waveguide can also be connected directly to the pawn.

The configuration of the present invention will be explained below using specific examples.

Figure 2 shows an electromagnetic horn and 1! which is used by fitting it into the opening at its tip! This is an example of a specific example of a magnetic lens. Reference numeral 14 denotes an electromagnetic lens, which is a feature of the present invention, and is used by fitting it into the tip of the horn 13 or 18 as shown by the arrow. 14 is an example of a single-sided convex lens. The surface shape of No. 14 was made to be a hyperboloid of rotation that approximately satisfies nd ``y''=c11)Cx-)~♂□n+]n+1 (z=y). Here, n is the refractive index and d is the focal length of the lens. A spherical shape may be used as a rough approximation. The electromagnetic lens was made of low dielectric loss materials such as polyethylene, polystyrene, Teflon, and paraffin.

As shown in FIG. 3, in addition to the (a) type single-sided convex lens, a (bl type double-convex lens) is also possible. (In the case of bl, the focal lengths on both sides do not necessarily have to be equal.

FIG. 4 shows a block diagram of the microwave circuit system used in the present invention. Electromagnetic bones for sending and receiving 13.
A pair of 18 were installed, and microwaves supplied via the circulator 39 were outputted from the transmitting horn 13, received by the receiving horn 18, and sent to the Magic 1 circuit 41 to detect microwave absorption.

The electromagnetic lenses were attached directly to the openings of the transmitting horn 13 and the receiving horn 18.

Microwaves emitted from a transmitting horn usually propagate as they spread through the air as spherical waves.

By using an electromagnetic lens, a spherical wave becomes a plane wave,
Since the spatial spread is constant, there is no microwave leakage, and the sample placed between the horns can be effectively irradiated with microwaves, improving detection sensitivity.

Next, the effect of using an electrothermal lens will be explained in detail using Example 9c.

Example 1 A double-convex lens of d = 150 wm was attached to both the transmitting and receiving horns, and when the horn spacing was arranged in the order of 45, growth was made on a GGG substrate with a diameter of 23 cm between the horns (YS , mLuB1Ca) m (The ESR (FMR) signal intensity of the FeGe 90K Carnet-Lpg film was approximately three times that of the case without using an electromagnetic lens.

Example 2 When a one-sided convex lens of d = 150 snow was attached to both the transmitting and receiving horns, and the distance between the horns was set to 45so+, noisy growth (YSmLuCa) was observed on a GGG substrate with a diameter of 231111 placed between the horns. s(FeGe)s
The MAR (FMR) signal intensity of the LPFi film was approximately twice that of the case without using an electromagnetic lens.

Example 38 When the EAR (FMR) signal strength was similarly measured using a d = 100 tone biconvex lens only for the transmitting horn, it was approximately 2.5 times as high as when no electromagnetic lens was used. One side of the biconvex lens used had a focal length of d':: 150 Wms and the other side had a focal length of +1=ioo, but the effect was almost the same.

Example 4 Double-sided convex lenses with a diameter of 100 m were attached to the transmitting and receiving horns, the distance between the horns was 200 m, and a garnet LPE film with a diameter of 50 m+ was placed between the horns. This film had an anisotropic magnetic field fluctuation within the wafer, but
When the sample position was moved, the resonant magnetic field varied. This is because the microwaves were concentrated (condensed) in a part of the wafer, allowing local excitation.

Example 5 A vacuum chuck was attached to a 50 m1 diameter wafer, and a mechanism for warping the wafer was attached. As a result of measurement using method 3, the resonant magnetic field changed in proportion to the amount of warpage of the wafer. Using this phenomenon, we were able to measure the magnetostriction constant.

The magnetic resonance apparatus of the present invention has the excellent features described in Japanese Patent Application No. 57-215075, and furthermore, the effect of the electromagnetic lens, which is a feature of the present invention, improves the % and enables local excitation. The range has expanded.

As mentioned above, the present invention has many characteristics and its industrial effects are significant.

[Brief explanation of drawings]

FIG. 1 is a diagram showing elements of the configuration of the present invention. In FIG. 1, 11.20......Microwave coaxial cable, 12.19...Coaxial equal wave type converter, ], 3. 18... Electromagnetic horn, 14.15...- Electromagnetic lens, 16.
......Sample, holder, 17...
・Sample, 21......, rail~22-...
...Electric mE, 23...Pole piece. FIG. 2 is an external view of the electromagnetic lens and electromagnetic horn of the present invention. Figure 3 is a side view of an electromagnetic lens, where (a) is a one-sided convex lens, and (b) is a double-sided convex lens. FIG. 4 is a block diagram of the microwave circuit used in the present invention. In Fig. 4 1ζ, 31...Gun power supply, 32...
・・Gun oscillator, 33・・・・・・・Hayamuki tongue, 34
...... Directional coupler, 35...
...Shutter, 36... Phaser, 37
・・・・・・・・・Delay line, 38・・・・・・・・・
・Rotary attenuator, 39... Circulator, 40... Crystal detector, 41...
・・・・・・・・・Magic T, 42・・・・・・・・・
Input quadrangle, 43... Preamplifier, 4
4・・・・・・・・・Amplifier, 45・・・・・・・・・
Modulation circuit, 4 &... Oscillator, 47...
... Phaser O 3 Figure ((2) (-e-) Figure 4

Claims (1)

[Claims] It has an electromagnetic horn for transmitting and an electromagnetic horn for receiving, and these two
In a magnetic resonance apparatus equipped with a sample holder for holding a sample between two electromagnetic horns, a dielectric 11-mount lens in the form of a monoconvex lens or a biconvex lens whose refracting surface is a hyperboloid of rotation is used as the two electromagnetic horns. A magnetic resonance apparatus characterized in that the apparatus is fitted into an opening of at least one of the electromagnetic horns.