JPH11195551A - Method of manufacturing magnet-integrated Faraday element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a magnet-integrated Faraday element, which can simplify a processing and assembling process and can easily and in large quantities supply a Faraday element at low cost. I do. SOLUTION: A medium having a Faraday effect is embedded in a magnetic paste, and then molded and fired to harden a magnet around the medium. A magnetic paste may be applied to a medium having a Faraday effect and fired. According to this manufacturing method, there is no need to assemble a separately formed medium having the Faraday effect and the permanent magnet, and the assembling process can be simplified. According to baking or baking, a medium having a Faraday effect having a fiber shape, a thin plate shape or a film shape on a substrate can be easily covered with a permanent magnet. Therefore, processing
The assembling process can be simplified, and the Faraday elements can be supplied easily and in large quantities at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a magnet-integrated Faraday element, and more particularly to a method of manufacturing a magnet-integrated Faraday element used for a high-capacity memory element, an optical isolator, and the like.

[0002]

2. Description of the Related Art In the modern highly information-oriented society represented by multimedia, it has been desired to simultaneously and accurately transmit and store a large amount of information such as languages, images, and news at the same time. Development of disks and the like is underway. In such an optical fiber, when light emitted from a light source is reflected by an end face of a repeater or a switch or a duplexer provided in the middle of a line, and enters the light source again, it causes noise. Further, in the case of a magneto-optical disk, the magnetic recording medium moves and rotates at a very high speed. Therefore, a signal detection method capable of following the high-speed movement and rotation is required. Therefore, a Faraday element is used for noise detection in an optical isolator or signal detection in a magneto-optical disk. The material used for the Faraday element, yttrium iron garnet single crystal having a large Faraday effect (Y ₃ Fe ₅ O _12: hereinafter, referred to as YIG) magnetic garnet single crystals containing iron typified by is typical.

FIG. 12 is a partially cutaway perspective view showing an example of an optical isolator using a Faraday element formed of a magnetic garnet single crystal. The optical isolator 1 shown in FIG. 12 includes a disk-shaped Faraday rotator 2 as a Faraday element. The Faraday rotator 2 is, for example, Y
It is formed of an IG single crystal. And Faraday rotator 2
The ring-shaped magnet 3 for applying a magnetic field is arranged so as to surround the periphery. As the magnetic field applying magnet 3, a rare earth magnet such as an Sm-Co alloy is generally used. The magnetic field applying magnet 3 is sandwiched by ring-shaped yokes 4 from both sides in the thickness direction. Further, before and after the light incident direction of the Faraday rotator 2, a substantially columnar polarizer 5 and an analyzer 6 whose polarization planes are adjusted to be shifted from each other by 45 ° are arranged.

FIG. 13 is an illustrative view showing an operation of the optical isolator shown in FIG. When the light emitted from the light source enters the polarizer 5, the light L having a polarization plane in the vertical direction
Only 1 passes through and enters the Faraday rotator 2. The light incident on the Faraday rotator 2 has its polarization plane rotated by 45 °. Then, the light L2 whose polarization plane is rotated by 45 ° passes through the analyzer 6. When a part of the light that has passed through the analyzer 6 is reflected by a repeater or the like (not shown) connected to the subsequent stage of the optical isolator 1 and enters the Faraday rotator 2 again, the polarization plane further increases in the same direction as the outward path. Rotate 45 °. The light L3 whose polarization plane has been rotated by a total of 90 ° is not incident on the light source because it is blocked by the polarizer 5. Therefore, noise and the like in optical communication are prevented.

[0005]

Conventionally, as a method for producing a magnetic garnet single crystal, LPE (Liquid P
Hase epitaxy) method and TSFZ (Trave
ling Solvent Floating Zon
e) The method is typical. Magnetic garnet single crystals obtained by these methods are usually several mm or more in diameter and several mm.
^{It has two} or more areas. However, the size of a Faraday rotator used for an optical isolator or the like has a diameter of about 1 m.
m, and a thickness of about several hundred μm. Therefore, when the LPE method or the TSFZ method is adopted, the obtained magnetic garnet single crystal must be processed to a predetermined diameter and thickness. In addition to the magnetic garnet single crystal, the magnet for applying a magnetic field must be processed into a ring shape as shown in FIG. Then, it is necessary to assemble the magnetic garnet single crystal and the magnet for applying a magnetic field. Such processing and assembly contributed to the high cost of Faraday elements such as optical isolators.

Therefore, a main object of the present invention is to provide a method of manufacturing a magnet-integrated Faraday element, which can simplify the processing and assembling steps and can easily and in large quantities supply the Faraday element at low cost. It is to be.

[0007]

According to the present invention, there is provided a method of manufacturing a magnet-integrated Faraday element, comprising the steps of preparing a medium having a Faraday effect, preparing a magnetic paste, and applying the magnetic paste to the medium. Baking the medium around the medium by firing. 2. A method of manufacturing a magnet-integrated Faraday element, comprising the steps of:

Further, according to the method of manufacturing a magnet-integrated Faraday element according to the present invention, there are provided a step of preparing a medium having a Faraday effect, a step of preparing a magnetic paste, and embedding the medium in the magnetic paste.
And baking the magnet around the medium by shaping and firing the Faraday element.

Furthermore, in the method for manufacturing a magnet-integrated Faraday element according to the present invention, the medium having the Faraday effect is preferably in the form of a fiber, a thin plate or a film on a substrate.

In the method of manufacturing a magnet-integrated Faraday element according to the present invention, the medium having the Faraday effect is preferably made of a metal oxide, an alloy or glass.

Further, in the method for manufacturing a magnet-integrated Faraday element according to the present invention, the magnet is preferably an alloy magnet, a ferrite magnet, or a rare earth magnet.

In the method for manufacturing a magnet-integrated Faraday element according to the present invention, a magnet having a Faraday effect is formed by baking or hardening a magnet on a medium having the Faraday effect to form a magnet-integrated Faraday element. There is no need to separately process and assemble the magnet and the magnet, and the processing and assembly process can be simplified. According to baking or baking, it is relatively easy to coat a medium having a Faraday effect having a fiber shape, a thin plate shape or a film shape on a substrate with a magnet to a desired thickness.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention with reference to the accompanying drawings.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first embodiment of the method for manufacturing a magnet-integrated Faraday element according to the present invention, first, a medium having a Faraday effect is prepared. Here, the Faraday effect means that the deflecting surface rotates when the linearly deflecting light is incident in the direction of the magnetic field or magnetization, and when the linearly deflecting light reciprocates, the deflecting surface rotates in the same direction as the forward direction. It is non-reciprocal. As a medium having the Faraday effect, for example, a YIG single crystal, a Ce: YIG single crystal in which a part of yttrium is replaced with cerium, or a medium such as Gd _2.7 Ce _0.3 Fe ₅ O ₁₂ or Tb _2.7 Ce _0.3
Garnet single crystal in which yttrium such as Fe ₅ O ₁₂ is replaced by gadolinium or terbium, or SrTiO ₃
And the like. Further, as a medium having the Faraday effect, for example, CdMnH
An alloy such as g, or a glass such as paramagnetic glass, magnetic glass, or lead glass doped with Tb can also be used. The medium having the Faraday effect is grown from the beginning in a fiber shape, a thin plate shape, or a film shape on a substrate. In order to obtain a fiber or a thin plate, for example, the TSFZ disclosed in Japanese Patent Application No. 8-93581 or the like is used.
A modified version of the method can be used. In order to obtain a thin plate or a film on a substrate, for example, LPE
Method can be used. That is, in the present invention,
A medium having the Faraday effect is grown from the beginning into a shape that can be applied as it is, for example, as a Faraday rotator. Therefore, the processing step of the medium having the Faraday effect, which has been conventionally required, can be simplified.

Next, a magnetic paste is prepared. As the magnet composition powder for forming the magnetic paste, Sm
Powders for producing rare earth magnets such as -Co alloy powder and Nd-Fe-B alloy powder, powders for producing ferrite magnets, and powders for producing alnico magnets are used. As the vehicle, an organic substance such as ethylene glycol or glycerin is used. Then, a magnetic paste is prepared by uniformly mixing the magnet composition powder and the vehicle in a container.

Next, a magnetic paste having a predetermined thickness is applied around the medium having the Faraday effect. That is, the medium is covered with the magnetic paste. This coating step is performed, for example, by inserting a medium having a Faraday effect into the magnetic paste in the above-described container and drying the medium as it is. According to this method, the thickness of the magnet printed around the medium having the Faraday effect can be easily adjusted. As another method, it may be applied with a brush, for example. Drying of the magnetic paste is performed by removing the vehicle by evaporation. The removal by evaporation is performed in a dryer at a temperature higher than the boiling point, for example, about 200 ° C. when ethylene glycol is used as a vehicle, and a dryer at a temperature of, for example, about 300 ° C. higher than the boiling point when glycerin is used. Made inside.

Next, the magnet is fired at a predetermined firing temperature, and the magnet is integrally fired on the medium. The firing temperature varies depending on the magnet composition used, but is approximately 1100 to 1100.
This is performed at a temperature of about 1300 ° C. When forming a rare earth magnet, it is necessary to perform firing in a reducing atmosphere.

Thus, a medium having a Faraday effect in which the magnets are integrally baked is obtained. Then, by cutting and polishing this to adjust the outer shape to the desired shape,
The magnet-integrated Faraday element according to the present invention is completed.
This magnet-integrated Faraday element can be used for, for example, a high-capacity memory element or an optical isolator.
In the optical isolator 1 shown in FIG. 2, the Faraday rotator 2 and the magnetic field applying magnet 3 are integrated. Therefore, it is not necessary to separately process and assemble the medium having the Faraday effect and the magnet as in the related art.
The assembly process can be simplified. According to the above-described baking process, it is relatively easy to coat a medium having a Faraday effect having a fiber shape, a thin plate shape, or a film shape on a substrate with a magnet having a desired thickness.

In the second embodiment of the method of manufacturing a magnet-integrated Faraday element according to the present invention, a medium having a Faraday effect and a magnetic paste are prepared in the same manner as in the first embodiment. Next, a plurality of media having the Faraday effect are inserted into the magnetic paste in one container while keeping a predetermined interval from each other. Then, after the vehicle is removed by evaporation in the same manner as in the above-described embodiment, the vehicle is fired at a predetermined firing temperature to harden the magnet. As a result, a lump in which a plurality of media having the Faraday effect are contained in the same magnet is obtained. The mass obtained in this manner is cut out together with a magnet for each medium, and the outer shape is finished to a predetermined shape, whereby a plurality of magnet-integrated Faraday elements according to the present invention are completed. According to the second embodiment, the same effect as that of the first embodiment can be obtained, and a large number of magnet-integrated Faraday elements can be manufactured at one time, so that the production efficiency increases.

A specific embodiment will be described below.

[0021]

(Embodiment 1) FIG. 1 is a process drawing showing an embodiment of a method of manufacturing a magnet-integrated Faraday element according to the present invention. In this example, in step 1, a fiber-like YIG single crystal having a diameter of 1 mm was produced using the single crystal growing apparatus 10 shown in FIG. FIG. 2A is a cross-sectional view of the single crystal growing apparatus 10 as viewed from the front.
(B) is a sectional view seen from a plane. This single crystal growing apparatus 10 is an apparatus for implementing a method obtained by improving the TSFZ method. Here, the single crystal growing apparatus 10 will be described.

This single crystal growing apparatus 10 includes a YAG laser generator 12 constituting a main heating apparatus. Two laser light emitting ports 16a and 16b are connected to the YAG laser generator 12 via fibers 14a and 14b. Further, single crystal growing apparatus 10 includes a housing 17. In the housing 17, a three-dimensional bi-elliptical mirror 18 surrounded by a bi-ellipse rotation surface obtained by rotating a bi-ellipse around its long axis is formed as a reflection plate. Here, the bi-ellipse is 2
It is a shape in which two ellipses are combined to share one focal point. The laser light emitting ports 16 a and 16 b penetrate the housing 17 and the bi-elliptical mirror 18, and are arranged to face each other with a central portion of a space surrounded by the bi-elliptical mirror 18 interposed therebetween. Within the bi-elliptical mirror 18, halogen lamps 20a, 20b
Are arranged at positions corresponding to the focal points of different ellipses. Double elliptical mirror 18 and halogen lamps 20a, 20
b constitutes an optical heating device as an auxiliary heating device. The halogen lamps 20a and 20b are light sources as heat sources. The light from the halogen lamps 20a and 20b is
The light is reflected by the inner surface of the bi-elliptical mirror 18 and is condensed to the common focal point F of the bi-ellipse. In addition, the above-described laser light emitting port 16
The laser beams from a and 16b are also emitted toward the common focal point F of the bi-ellipse in the bi-ellipse mirror 18. Therefore, the sample is heated by arranging the sample at the shared focal point in the center of the space surrounded by the bi-elliptical mirror 18. In addition, the output of the YAG laser and the halogen lamps 20a, 20
By adjusting the output of 0b, the temperature distribution and the temperature gradient can be set to optimal conditions. In the single crystal growing apparatus 10, at the common focus F, for example, 1700 ° C.
Although the temperature is of the order of magnitude, the surroundings are not heated, so that the temperature rapidly decreases as the distance from the common focal point F increases. Therefore, in the heating part and its vicinity,
A large and steep temperature gradient is formed.

An upper axis 22a and a lower axis 22b for holding a raw material rod and a seed crystal are arranged to face each other with a common focal point F interposed therebetween, surrounded by the double elliptical mirror 18. The upper shaft 22a and the lower shaft 22b extend from the inside to the outside of the bi-elliptical mirror 18, respectively, and
3a and the lower shaft moving device 23b. The upper shaft moving device 23a and the lower shaft moving device 23b
a and the lower shaft 22b are synchronously moved in the axial direction. The moving speed is preferably 1 mm to 8 mm
/ Hr. The moving speeds of the upper shaft 22a and the lower shaft 22b may be the same or different. For example, when the distance between the upper axis 22a and the lower axis 22b is gradually increased, a single crystal having a small thickness can be obtained, and the distance between the upper axis 22a and the lower axis 22b can be obtained. Is gradually approached, a thick single crystal can be obtained.

At the end corresponding to the lower shaft 22b of the upper shaft 22a, for example, a round bar-shaped, square bar-shaped, plate-shaped or other shaped YI
A magnetic garnet polycrystal such as G is fixed as the raw material rod 24. If a round rod is used as the raw material rod 24, a fiber-shaped single crystal having a circular cross section is obtained, and if a square rod is used, a fiber-shaped or thin plate-shaped single crystal having a rectangular cross section is obtained. Further, a seed crystal 25 such as a YIG single crystal is fixed to an end corresponding to the upper shaft 22a of the lower shaft 22b. By holding the raw material rod 24 and the seed crystal 25 in this way, both are brought into abutment. The seed crystal 25 may be attached to the upper shaft 22a, and the raw material rod 24 may be attached to the lower shaft 22b. Also, instead of the raw material rod 24, for example, a magnetic garnet polycrystal is applied in the form of a slurry on the surface of a GGG substrate, and the raw material 24 is dried.
May be used. In that case, a thin or thin magnetic garnet single crystal can be obtained on the GGG substrate. In this case, in order to hold and move the raw material 24, only one of the upper shaft 22a and the lower shaft 22b may be used. The upper shaft 22a, the lower shaft 22b,
The raw material rod 24, the seed crystal 25 and the obtained single crystal 28
It is stored in a quartz tube 27. The atmosphere in the quartz tube 27 is appropriately adjusted by, for example, introducing Ar gas or O ₂ gas in accordance with the single crystal manufacturing conditions.

In order to produce a magnetic garnet single crystal with this single crystal growing apparatus 10, first, a seed crystal 25
Is placed at the common focal point F. Next, the end of the raw material rod 24 is heated to about 1700 ° C. and melted by the main heating device and the auxiliary heating device.
Are brought into contact with each other to form a fusion zone 26.
That is, the fusion zone 26 is formed by the common focal point F of the bi-elliptical mirror 18.
Is formed at a position corresponding to. By moving the upper shaft 22a and the lower shaft 22b in the axial direction as described above, the molten zone 26 extends from one end to the other end of the raw material rod 24.
To move. As a result, heat melting and cooling and solidification are continuously performed, and a target magnetic garnet single crystal can be obtained. By using this single crystal growing apparatus 10, a magnetic garnet single crystal having a size matching the size of an element such as a Faraday rotator can be obtained from the beginning. For this reason, the process of processing a large lump of magnetic garnet single crystal, which has been conventionally required, into a device shape can be simplified, and the use efficiency of the material can be increased. Further, according to the single crystal growing apparatus 10, since a crucible or a flux is not used, a high-purity single crystal can be grown.

Next, in Example 1, in step S2, the Sm-Co alloy powder and the vehicle were uniformly mixed in a container to prepare a magnetic paste. As this container, for example, a cylindrical container having a diameter of about 4 mm is used. The diameter of the container is changed according to the thickness of the magnet to be used.

Next, in step S3, as shown in FIG. 3, the YIG single crystal fiber obtained in step S1 was inserted and embedded in the magnetic paste created in step S2. Then, in step S4, about 200
The vehicle was removed by heating to between 300C and 300C and dried.

Next, in step S5, the magnetic paste applied to the periphery of the YIG single crystal fiber and dried are taken out of the container, and while applying a magnetic field in the axial direction of the YIG single crystal fiber, for example, 100 to 5 mm
Press molding was performed under a pressure of 00 kgf / cm ² . This press molding is performed to make the outer shape the intended shape and to increase the reactivity in the subsequent firing step. Press molding in a magnetic field is performed to align the magnetization directions of the magnet powder in one direction.

Next, in step S6, in order to sinter the press-formed product, for example, a pressure of 11
It baked at 00-1300 degreeC. In this way, the one obtained by integrally sintering the magnet around the YIG single crystal fiber as shown in FIG. 4 was obtained. This was cut to a predetermined thickness in step S7, and the end face was polished to adjust the outer shape, thereby obtaining a magnet-integrated Faraday element as shown in FIG. When a polarizer inclined at 45 ° to each other was arranged on both sides in the thickness direction of the magnet-integrated Faraday element shown in FIG. 5, laser light having a wavelength of 1300 nm was irradiated.
A Faraday rotation angle of 45 ° was indicated.

Example 2 A magnet-integrated Faraday element was manufactured in the same manner as in Example 1, except that the alloy powder for magnet production in Example 1 was replaced with an Nd—Fe—B alloy. Polarizers inclined at an angle of 45 ° were arranged on both sides in the thickness direction of the magnet-integrated Faraday element, and a laser beam having a wavelength of 1300 nm was irradiated. As a result, a Faraday rotation angle of 45 ° was exhibited.

(Embodiment 3) In the same manner as in Embodiment 1, YIG
A plurality of single crystal fibers were grown. In addition, a magnetic paste was prepared using Sm-Co alloy powder as the alloy powder for magnet production. Then, a plurality of YIG single crystal fibers were inserted and embedded in the magnetic paste while keeping a predetermined interval from each other. Then, about 200-3
The vehicle was removed by evaporation at a temperature of 00 ° C. Further, after press molding in a magnetic field, by firing, a magnet containing the embedded number of YIG single crystal fibers was obtained as shown in FIG. Thereafter, each YIG single crystal fiber was cut together with a magnet and processed into a desired shape and thickness to obtain a magnet-integrated Faraday element similar to that shown in FIG. Then, when laser light having a wavelength of 1300 nm was irradiated in the same manner as in Example 1, 45
° Faraday rotation angle.

Example 4 A magnet-integrated Faraday element was produced in the same manner as in Example 3, except that the alloy powder for producing a magnet of Example 3 was changed to Nd-Fe-B. This Faraday element with a built-in magnet also exhibited a Faraday rotation angle of 45 ° by irradiation with a laser beam having a wavelength of 1300 nm, as in Example 1.

Example 5 Using a single crystal growing apparatus 10 shown in FIG. 1, a Ce: YIG single crystal in which part of yttrium is replaced by cerium (for example, Y _2.7 Ce _O.3 O ₁₂ )
Was prepared. Using the obtained Ce: YIG single crystal fiber, a magnet-integrated Faraday element was formed in the same manner as in Examples 1 to 4. This magnet-integrated Faraday element also has a wavelength of 1300 nm as in the first embodiment.
The laser beam irradiation showed a Faraday rotation angle of 45 °.

Example 6 A thin plate of YI was formed by the LPE method.
A plurality of G single crystals were produced. This was inserted and embedded in the magnetic paste in the same manner as in Example 3. After that, about 200 ~
The vehicle was evaporated off at a temperature of 300 ° C. Further, after press-molding in a magnetic field, the resultant was fired to obtain a magnet including the embedded number of YIG single-crystal thin plates as shown in FIG. Thereafter, each YIG single crystal thin plate was cut together with a magnet and processed into a shape as shown in FIG. This was further processed to a predetermined thickness to obtain a magnet-integrated Faraday element as shown in FIG. On the other hand, Embodiment 1
When a laser beam having a wavelength of 1300 nm was irradiated in the same manner as described above, a Faraday rotation angle of 45 ° was exhibited.

(Embodiment 7) Y of YIG is changed to Gd or Tb.
, The saturation magnetization of the magnetic garnet decreases, the temperature characteristics are improved, and the externally applied magnetic field can be reduced. In this case, the magnet can be changed from an expensive rare earth magnet to an inexpensive ferrite magnet or alnico magnet. Therefore, a single crystal of Gd _2.7 Ce _0.3 Fe ₅ O ₁₂ (Gd, Ce garnet single crystal) was manufactured, and a magnet-integrated Faraday element in which a ferrite magnet was integrated was manufactured in the same manner as in Examples 5 and 6. . As a result, a Faraday rotation angle of 45 ° was obtained by irradiation with a laser beam having a wavelength of 1300 nm as in Example 1. A similar effect could be obtained with a magnet-integrated Faraday element using an alnico magnet instead of a ferrite magnet.

Example 8 A magnet-integrated Faraday element was formed in the same manner as in Examples 1 to 7, except that glass exhibiting the Faraday effect was used instead of the YIG single crystal fiber. Further, Cd, which is an alloy having a Faraday effect,
A magnet-integrated Faraday element was formed using MnHg in the same manner as in the above-described embodiments. Further, a magnet-integrated Faraday element was formed using SrTiO ₃ , which is an oxide material having a Faraday effect, in the same manner as in the above-described embodiments. Each of these magnet-integrated Faraday elements was irradiated with a laser beam having a wavelength of 1300 nm to form a 45 °
The Faraday rotation angle was shown.

Example 9 A thin-film YIG single crystal was formed on a GGG substrate by the LPE method. A magnetic paste was applied to both sides in the thickness direction and baked. This application may be by printing, for example. Thereafter, the resultant was baked through the same steps as in the above-described embodiments, to obtain a magnet-integrated Faraday element as shown in FIGS.
On the other hand, when a laser beam having a wavelength of 1300 nm was irradiated in the same manner as in Example 1, the Faraday rotation angle was 45 °.

The manufacturing method according to the present invention can be applied not only to a Faraday element but also to, for example, a magnetostatic wave element.

[0039]

As is apparent from the above description, according to the present invention, a permanent magnet is burned on a medium having a Faraday effect, or a permanent magnet is baked and hardened around a medium having a Faraday effect. Since the Faraday element is formed, there is no need to assemble a separately formed medium having a Faraday effect and a permanent magnet as in the related art,
The assembly process can be simplified. According to baking or baking, a medium having a Faraday effect having a fiber shape, a thin plate shape or a film shape on a substrate can be easily covered with a permanent magnet. Therefore, the processing / assembly process can be simplified, and the Faraday element can be supplied easily and in large quantities at low cost.

[Brief description of the drawings]

FIG. 1 is a process chart showing one embodiment of a method for manufacturing a magnet-integrated Faraday element according to the present invention.

FIG. 2A is a schematic cross-sectional view of an example of a single crystal growing apparatus as viewed from the front, and FIG. 2B is a schematic cross-sectional view as viewed from a plane.

FIG. 3 is an illustrative view showing a step S3 in the embodiment shown in FIG. 1;

FIG. 4 is a schematic perspective view showing a state in which a magnet is integrally sintered around a YIG single crystal fiber in the embodiment shown in FIG. 1;

FIG. 5 is a perspective view showing an example of a magnet-integrated Faraday element according to the present invention.

FIG. 6 shows a plurality of YIs according to another embodiment of the present invention.
FIG. 4 is a schematic perspective view showing a state where a magnet is integrally sintered around a G single crystal fiber.

FIG. 7 is a schematic perspective view showing a state in which magnets are integrally sintered around a plurality of YIG single crystal thin plates in still another embodiment according to the present invention.

FIG. 8 shows YI in still another embodiment of the present invention.
FIG. 4 is a schematic perspective view showing a state where a magnet is integrally sintered around a G single crystal fiber.

FIG. 9 is a perspective view showing another example of the magnet-integrated Faraday element according to the present invention.

FIG. 10 is a perspective view showing a state in which magnets are integrally sintered on both surfaces in the thickness direction of a YIG single crystal thin film on a GGG substrate in another embodiment according to the present invention.

FIG. 11 is a sectional view taken along line XI-XI in FIG. 10;

FIG. 12 is a partially cutaway perspective view showing an example of an optical isolator using a Faraday element formed of a magnetic garnet single crystal.

FIG. 13 is an illustrative view showing a function of the optical isolator shown in FIG. 12;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical isolator 2 Faraday rotator 3 Magnet for applying a magnetic field 4 Yoke 5 Polarizer 6 Analyzer 10 Single crystal growing device 12 YAG laser generator 16a, 16b Laser light emitting port 18 Biaval mirror 20a, 20b Halogen lamp 24 Material rod 25 Seed crystal 26

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masakatsu Okada 22 Cosmo Nijo 110, Jurakudanigashi-cho, Nakagyo-ku, Kyoto 110

Claims (5)

[Claims] A step of preparing a medium having a Faraday effect, a step of preparing a magnetic paste, and a step of applying the magnetic paste to the medium and firing the magnet around the medium by firing. A method for manufacturing a magnet-integrated Faraday element. 2. A step of preparing a medium having a Faraday effect, a step of preparing a magnetic paste, embedding the medium in the magnetic paste, and molding and firing the same to form a magnet around the medium. A method for manufacturing a magnet-integrated Faraday element, comprising a step of baking. 3. The method for manufacturing a magnet-integrated Faraday element according to claim 1, wherein the shape of the medium having the Faraday effect is a fiber shape, a thin plate shape, or a film on a substrate. 4. The method for manufacturing a magnet-integrated Faraday element according to claim 1, wherein the medium having the Faraday effect is made of a metal oxide, an alloy, or glass. 5. The magnet according to claim 1, wherein the magnet is an alloy magnet, a ferrite magnet, or a rare earth magnet.
The method for manufacturing a magnet-integrated Faraday element according to any one of the above.