TW201708159A - Magneto-optical material, method for producing same and magneto-optical device - Google Patents

Abstract

Provided, as a transparent magneto-optical material which does not absorb fiber laser light within a wavelength range of 0.9-1.1 [mu]m and is thus suitable for constituting a magneto-optical device such as an optical isolator wherein the formation of a thermal lens is suppressed, is a magneto-optical material which is composed of a transparent ceramic that contains a composite oxide represented by formula (1) as a main component, or which is composed of a single crystal of a composite oxide represented by formula (1). Tb2xR2(2-x)O8-x (1) (In the formula, 0.800 < x < 1.00, and R represents at least one element selected from the group consisting of silicon, germanium, titanium, tantalum, tin, hafnium and zirconium (excluding the cases where R represents only silicon, germanium or tantalum)).

Description

Magnetic optical material, manufacturing method thereof, and magnetic optical device

The present invention relates to a magnetic optical material and a magnetic optical device, and more particularly to a magnetic optical material composed of a transparent ceramic or a single crystal containing a composite oxide, which is suitable for a magnetic optical device constituting an optical isolator or the like, and a manufacturing thereof A method, and a magnetic optical device using the magnetic optical material.

In recent years, high output has become possible, and the popularity of laser processing machines using fiber lasers has been remarkable. Further, when the laser light source incorporated in the laser processing machine is incident from the outside, the resonance state is not stabilized, and the oscillation state is disturbed. In particular, if the oscillated light is reflected by the optical system on the way and returned to the light source, the oscillation state is greatly disturbed. In order to prevent this, an optical isolator is usually provided in front of the light source or the like.

The optical isolator is composed of a Faraday rotator, a polarizer disposed on the light incident side of the Faraday rotator, and an analyzer disposed on the light exit side of the Faraday rotator. Further, the Faraday rotator system applies a magnetic field in parallel with the traveling direction of the light. At this point, the polarization of the light is tied to Farah No advance or retreat in the first rotor will only rotate in a certain direction. Furthermore, the polarization section of the Faraday rotator light is adjusted to a length of exactly 45 degrees of rotation. Here, when the polarization plane of the polarizer and the analyzer is shifted by 45 degrees in the direction of rotation of the forward light, the polarization of the forward light is transmitted because the position of the polarizer coincides with the position of the analyzer. On the other hand, the polarization of the retreating light is rotated 45 degrees counterclockwise with respect to the offset angle direction of the plane of polarization of the polarizer shifted by 45 degrees from the analyzer position. Therefore, the polarization plane of the returning light at the position of the polarizer is shifted by 45 degrees - (-45 degrees) = 90 degrees with respect to the plane of polarization of the polarizer, and cannot pass through the polarizer. The light that has proceeded in this way is transmitted and emitted, and the light that has been retracted functions as an optical isolator that blocks.

As described above, in the material used as the Faraday rotator constituting the optical isolator, TGG crystals (Tb ₃ Ga ₅ O ₁₂ ) or TSAG crystals (Tb _(3-x) Sc ₂ Al ₃ O ₁₂ ) have been known (Japanese special Japanese Laid-Open Patent Publication No. JP-A-2002-293693 (Patent Document 2)). The TGG crystal has a large Verdet constant of 40 rad/(T.m) (i.e., 0.14 min/(Oe.cm)) and is currently widely used as a standard fiber laser device. The TSAG crystal has a reduction constant of about 1.3 times that of the TGG crystal (that is, about 0.18 min/(Oe.cm)), which is also a material that is mounted on a fiber laser device.

In addition to the above, JP-A-2010-285299 (Patent Document 3) discloses (Tb _x R _1-x ) ₂ O ₃ (x-based 0.4≦x≦1.0), and R is derived from 钪, 钇, A single crystal or ceramic in which an oxide selected from the group consisting of ruthenium, osmium, iridium, osmium, iridium, and osmium is used as a main component. The oxide-based constant of the above-mentioned components is 0.18 min/(Oe.cm) or more, and in the examples, the maximum is 0.33 min/(Oe.cm). Further, in the same document, the TGD has a cutting constant of 0.13 min/(Oe.cm). The difference between the two is actually 2.5 times.

An oxide composed of substantially the same component is also disclosed in Japanese Laid-Open Patent Publication No. 2011-121837 (Patent Document 4), and it is described that it has a larger cutting constant than a TGG single crystal.

As in the case of the above-mentioned Patent Documents 3 and 4, when an optical isolator having a large reduction constant is obtained, the total length necessary for the rotation of 45 degrees can be shortened, and the optical isolator can be reduced in size.

However, the above Patent Documents 3 and 4 disclosed _{(Tb x R 1-x)} 2 O 3 oxide, although indeed TGG crystal disclosed in Patent Document 1, the Patent Document 3 herein or in the crystalline and the mentioned TGG In contrast, the reduction constant is 1.4 to 2.5 times, which is very large, but the oxide is only a small amount, but it still absorbs the optical fiber laser light using the desired wavelength range of 0.9 to 1.1 μm. In recent years, optical fiber laser devices have almost reduced output, and even if they are mounted as optical isolators with a small amount of absorption, they cause problems due to deterioration of beam quality due to the thermal lens effect.

In the same manner, a material having a very large cutting constant per unit length and having a yttrium iron garnet (general name: YIG) containing iron (Fe) (Japanese Patent Laid-Open Publication No. 2000-266947 (Patent Document 5)) . However, iron (Fe) has a large light absorption at a wavelength of 0.9 μm. This optical absorption occurs in an optical isolator with a wavelength in the range of 0.9 to 1.1 μm. Therefore, an optical isolator using this yttrium iron garnet single crystal is extremely difficult to utilize a fiber laser device which has a high tendency to be high in output.

Further, the garnet-type oxide of the TGG crystal (Tb ₃ Ga ₅ O ₁₂ ) or the TSAG crystal ((Tb _(3-x) Sc _x ) Sc ₂ Al ₃ O ₁₂ ) belongs to the stoichiometry. In comparison with the fact that it is easy to form a crystal phase other than the garnet structure, it is generally known among the industry, and the rapid decrease in light transmittance or the decrease in yield due to compositional deviation when the raw material is blended is a problem.

As an alternative to such an existing material, an oxide having a crystal structure of a pyrochlore type can be cited. The pyrochlore type crystal system has a crystal structure of A ₂ B ₂ O ₇ , and has a cubic crystal structure when the radius ratio of the A ion to the B ion is within a certain range, which is known to the public. When a crystal structure is selected as a material for forming a cubic crystal, the single crystal system is of course capable of producing a material having high transparency even if it is a ceramic magnet, and thus it is expected to be used as various optical materials.

An example of such a pyrochlore-type material is disclosed in Japanese Laid-Open Patent Publication No. 2005-330138 (Patent Document 6), which is a cubic-crystalline titanium oxide pyrochlore sintered body having a rare earth in the A portion. In the cubic crystal titanium oxide pyrochlore of element RE, the element RE of the A site is composed of elements of Lu, Yb, Tm, Er, Ho, Y, Sc, Dy, Tb, Gd, Eu, Sm, and Ce. One or more of the composite oxides RE _2-x Ti ₂ O _{7-δ formed} by the fact that the indefinite ratio x of the A-site element RE corresponds to the A-site element RE The electronically conductive ceramic powder in the range of 0 < x < 0.5 is sintered and then subjected to a reduction treatment. Since the use is an electronically conductive ceramic, there is no mention of the transparency of the sintered body, and it is generally sintered, and the completion of the generally opaque sintered body is known to the industry, although it is presumed that the material described in Patent Document 6 is not available. As an optical material, information on the fact that the titanium oxide greenstone containing Tb can be cubic crystal is disclosed by the patent document 6.

However, it has been previously known that the square crystal cannot be formed in the oxide of pure Tb ("Rare earth disilicates R2Si2O7 (R=Gd, Tb, Dy, Ho): type B", Z., Kristallogr., Vol. 218 No. 12 795-801 (Non-Patent Document 1)).

In the same period, the fact that there is no Tb at all, but a certain rare earth lanthanum oxide forms a cubic crystal structure and has translucency ("Fabrication of transparent La ₂ Hf ₂ O ₇ ceramics from combustion" Synthesized powders", Mat. Res. Bull. 40 (3) 553-559 (2005) (Non-Patent Document 2)).

Further, in Japanese Laid-Open Patent Publication No. 2010-241677 (Patent Document 7), an optical ceramic having at least 95% by weight of each crystal, preferably at least 98% by weight, is a cubic chlorite or fluorite structure. And contains stoichiometric compound A _2+x B _y D _z E ₇

Here, -1.15≦x≦0 and 0≦y≦3 and 0≦x≦1.6 and 3x+4y+5z=8, and A is a valence of at least one selected from the group of rare earth metal oxides. a cation, B is at least one tetravalent cation, D is at least one pentavalent cation, and E is a polycrystalline or transparent optical ceramic having at least one divalent anion of E, and A is composed of Y, Gd, Yb, Lu, Sc, and Selected from La, B is selected from Ti, Zr, Hf, Sn, and Ge. It is confirmed that titanium oxide, zirconium oxide, niobium oxide, and tin oxide containing several kinds of rare earths are not contained at all. The material and the lanthanum oxide structure may be 98% by weight or more of a cubic yellow chlorite (pyrochlore) structure.

Further, the pyrochlore-type oxide system exhibits a stoichiometric ratio of 1 to 1 which is an ideal pyrochlore structure even if the blend ratio of the formed A ions and B ions is deviated, and the cubic crystal pyrochlore is also allowed to exhibit in a certain range. In contrast, it is speculated that the sharp decrease in light transmittance or the decrease in yield due to compositional deviation when the raw material is blended as seen in the garnet-type oxide can be suppressed ("Phase equilibria in the refractory oxide systems of zirconia," Hafnia and yttria with rare-earth oxides", J. Eur. Ceram. Soc. 28 2363-2388 (2008) (Non-Patent Document 3), "Stuffed rare earth pyrochlore solid solutions", J. solid state chem. 179 3126- 3135 (2006) (Non-Patent Document 4)).

However, there has been no pyrochlore-type oxide until now, and while maintaining the cubic crystal structure containing Tb ions, the blend ratio of A ions and B ions is further deviated from the stoichiometric ratio, thereby making it transparent. A more well-known example of a magnetic optical material that can be utilized for high output lasers.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2011-213552

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2002-293693

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2010-285299

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2011-121837

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2000-266947

[Patent Document 6] Japanese Patent Laid-Open Publication No. 2005-330133

[Patent Document 7] Japanese Patent Laid-Open Publication No. 2010-241677

[Non-patent literature]

[Non-Patent Document 1] "Rare earth disilicates R2Si2O7 (R = Gd, Tb, Dy, Ho) : type B", Z., Kristallogr., Vol. 218 No. 12 795-801 (2003)

[Non-Patent Document 2] "Fabrication of transparent La ₂ Hf ₂ O ₇ ceramics from combustion synthesized powders", Mat. Res. Bull. 40 (3) 553-559 (2005)

[Non-Patent Document 3] "Phase equilibria in the refractory oxide systems of zirconia, hafnia and yttria with rare-earth oxides", J. Eur. Ceram. Soc. 28 2363-2388 (2008)

[Non-Patent Document 4] "Stuffed rare earth pyrochlore solid Solutions", J. solid state chem. 179 3126-3135 (2006)

The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetic optical material which is suitable for constituting an optical isolator which suppresses the occurrence of a thermal lens by not absorbing laser light of a fiber having a wavelength range of 0.9 to 1.1 μm. A transparent magnetic optical material of a magnetic optical device, a method of manufacturing the same, and a magnetic optical device.

The present inventors have based on the above prior art findings as a fiber laser light having a wavelength range of 0.9 to 1.1 μm as compared with the (Tb _x R _1-x ) ₂ O ₃ oxide ceramic. In view of the new material candidates for power laser applications, various pyrochlore-type materials including Tb are investigated, and magnetic optical materials and magnetic optical devices suitable for constituting magnetic optical devices such as optical isolators are completed.

That is, the present invention provides the following magnetic optical material, a method for producing the same, and a magnetic optical device.

[1] A magnetic optical material comprising: a transparent ceramic containing a composite oxide represented by the following formula (1) as a main component or a single crystal of a composite oxide represented by the following formula (1); , Tb _2x R _2(2-x) O _8-x (1) (wherein, 0.800 < x < 1.00, R is selected from the group consisting of ruthenium, osmium, titanium, iridium, tin, iridium, zirconium At least 1 element (however, for 矽, 锗, and 钽, it is excluded as the element alone)).

[2] The magnetic optical material according to [1], wherein, when the laser light having a wavelength of 1064 nm is incident at a beam diameter of 1.6 mm as a light path length of 10 mm, the maximum value of the incident power of the laser light that does not generate the thermal lens is 30W or more.

[3] The magnetic optical material according to [1] or [2], wherein the linear transmittance of light having a wavelength of 1064 nm per optical path length of 10 mm is 90% or more.

[4] The magnetic optical material according to any one of [1] to [3], wherein the cubic crystal having a pyrochlore crystal lattice is a main phase.

[5] A method for producing a magnetic optical material, which comprises at least one oxide powder selected from the group consisting of cerium oxide, lanthanum, titanium, cerium, tin, cerium, and zirconium (however, In the case of 锗, 钽 and 钽, the firing of the raw material is carried out in a crucible, and a calcined raw material containing a cubic pyrochlore-type oxide as a main component is produced, and the calcined raw material is pulverized. The raw material powder is formed into a predetermined shape and then sintered, and further subjected to a heat-to-pressure equalization treatment to obtain a sintered body of a transparent ceramic containing a composite oxide represented by the following formula (1) as a main component, Tb _2x R _2(2-x) O _8-x (1) (wherein, 0.800 < x < 1.00, R is at least 1 selected from the group consisting of ruthenium, osmium, titanium, ruthenium, tin, osmium, zirconium) Elements (however, for 矽, 锗, and 钽, exclude the element alone)).

[6] The method for producing a magnetic optical material according to [5], wherein the cerium oxide powder and at least one oxide selected from the group consisting of cerium, lanthanum, titanium, cerium, tin, cerium, and zirconium are at least one oxide. a powder having a molar ratio of at least one atom selected from the group consisting of ruthenium, rhodium, titanium, osmium, tin, iridium, and zirconium to x: (2-x) (however, x After weighing and mixing in a manner of more than 0.800 and less than 1.00), the mixture is fired in a crucible.

[7] A magnetic optical device comprising the magnetic optical material according to any one of [1] to [4].

[8] The magnetic optical device according to [7], which is an optical isolator usable in a wavelength range of 0.9 μm or more and 1.1 μm or less, wherein the optical isolator comprises the above-mentioned magnetic optical material as a Faraday rotator, and the Faraday A polarizing material is provided on the optical axis of the rotor.

[9] The magnetic optical device according to [8], wherein the Faraday rotator has an anti-reflection film on an optical surface thereof.

According to the present invention, it is possible to provide a transparent magnetic optical material which is suitable for constituting compared to (Tb _x R _1-x ) ₂ O ₃ oxide, which does not generate a thermal lens and has a maximum laser light incident power, even if A magnetic optical device such as an optical isolator that is mounted on a fiber laser device with a wavelength range of 0.9 to 1.1 μm and whose beam quality is not degraded.

100‧‧‧Optical isolator

110‧‧‧Faraday rotor

120‧‧‧Polar mirror

130‧‧‧Analyzer

140‧‧‧ magnet

[Fig. 1] Fig. 1 is a schematic cross-sectional view showing a configuration example of an optical isolator using the magnetic optical material of the present invention as a Faraday rotator.

[Fig. 2] A ceramic sintered body of Reference Example 1-1, Examples 1-3, 1-4, and Comparative Examples 1-1 and 1-2 (Tb _2x Hf _2(2-x) O _8-x ) X-ray diffraction pattern.

[Fig. 3] is an enlarged view of an X-ray diffraction pattern in the vicinity of θ = 15° in Fig. 2 .

[Fig. 4] is an enlarged view of an X-ray diffraction pattern in the vicinity of θ = 50° in Fig. 2 .

[Magnetic Optical Materials]

Hereinafter, the magnetic optical material of the present invention will be described.

The magnetic optical material of the present invention is composed of a transparent ceramic containing a composite oxide represented by the following formula (1) as a main component or a single crystal of a composite oxide represented by the following formula (1), Tb _2x R _{2 (2-x)} O _8-x (1) (wherein, 0.800 < x < 1.00, R is at least one element selected from the group consisting of ruthenium, osmium, titanium, iridium, tin, iridium, and zirconium ( However, in the case of 矽, 锗 and 钽, the exclusion is solely for this element)).

鋱 (Tb) is a material having the largest reduction constant among paramagnetic elements other than iron (Fe), and is transparent at a wavelength of 1.06 μm (linear transmittance of light having a light path length of 1 mm is 80% or more) Therefore, it is the most suitable element for optical isolators in this wavelength range. However, in order to utilize this transparency, ruthenium is not in a metal bond state, but must be a stable compound state.

Here, the most typical form of the compound which forms a stable compound is an oxide. Among them, a material having a pyrochlore type structure (composite oxide) is formed by a cubic crystal structure (referred to as a cubic crystal having a pyrochlore crystal lattice (gypsumite type cubic crystal)), and thus A highly transparent compound that is free of anisotropic scattering is obtained. Therefore, a compound which is a pyrochlore-type oxide and which has a cubic crystal structure and a cubic crystal-based pyrochlore-type oxide which is formed by a system which enters the A site is preferably used in a wavelength range of 0.9 μm. Above, 1.1 μm or less, more specifically, a material of an optical isolator of 1,064 ± 40 nm.

Further, as the B-site element for establishing the cubic crystal structure, ruthenium, rhodium, titanium, iridium, tin, iridium, and zirconium can be suitably used.

However, since the yttrium or lanthanum is too small in ionic radius, if the B portion is filled only with such an element, it becomes an orthorhombic crystal and hinders transparency, which is not preferable. Therefore, the case where ruthenium or osmium is selected is utilized in combination with zirconium of other elements having a larger ionic radius.

As a result, the magnetic optical material of the present invention is preferably a cubic crystal having a pyrochlore crystal lattice (a pyrochlore type cubic crystal) as a main phase, and more preferably a pyrochlore type cubic crystal. In addition, the main phase means that the pyrochlore type cubic crystal accounts for 90% by volume or more, preferably 95% by volume or more, as a crystal structure. Or the calcination rate calculated from the powder X-ray diffraction result of the magnetic optical material is 51.5% or more in the case where R alone is zirconium in the above formula (1), and R is another case (that is, , R is at least one element selected from the group consisting of ruthenium, osmium, titanium, iridium, tin, antimony, and zirconium (however, in the case of yttrium, yttrium, and yttrium, the element is excluded) 97.3% or more, preferably more than 99%.

In addition, the pyrochlore ratio refers to the peak position of the (622) plane corresponding to the cubic crystal by the powder X-ray diffraction of the target material (the value of 2 θ P ₍₆₂₂₎ ), according to Wegard's law (Vegard's law) Use the value of 2 θ (P _Tb ) of the (622) plane of _{yttrium oxide and} the value of 2 θ (P _TbR ) of the (622) plane in the case where the target material is an ideal pyrochlore type cubic crystal. The molar fraction of the ideal pyrochlore-type cubic crystal which is occupied by the above-mentioned target material. Further, the (622) surface is a diffractive surface of the highest angle side among the four main diffraction surfaces of the x-ray diffraction pattern of the pyrochlore type cubic crystal.

In the above formula (1), at least one element selected from the group consisting of ruthenium, osmium, titanium, iridium, ruthenium, osmium, and zirconium is used. It is excluded from being alone in this element, but may further contain other elements. As other elements, if it is a rare earth element, it can be exemplified: 镧, 釓, 銩, 铈, 鐠, 镱, 镝, as Various impurity groups are typically exemplified by calcium, aluminum, phosphorus, tungsten, molybdenum, and the like.

The content of the other element is preferably 10 or less, more preferably 1 or less, still more preferably 0.1 or less, and particularly preferably 0.001 or less (substantially zero) when the total amount of lanthanum is 100.

In the formula (1), the x-form is more than 0.800, less than 1.00, preferably 0.900 or more, less than 1.00, more preferably 0.950 or more, less than 1.00, and particularly preferably 0.950 or more and 0.999 or less. In the case where x is in this range, since R ions preferentially occupy the B site, the Tb ions efficiently occupy the A side, so that the valence (trivalent) stability of Tb is improved and the light transmittance is improved. However, when x is 0.800 or less, the pyrochlore-type cubic crystal does not become a main phase, and further, it becomes a mixed crystal and produces birefringence. As a result, light transmittance is remarkably lowered, which is not preferable.

The magnetic optical material of the present invention contains the composite oxide represented by the above formula (1) as a main component. In other words, the magnetic optical material of the present invention may contain a composite oxide represented by the above formula (1) as a main component, and may optionally contain other components as an auxiliary component.

Here, the term "containing as a main component" means containing 50% by mass or more of the composite oxide represented by the above formula (1). The content of the composite oxide represented by the formula (1) is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 99% by mass or more, and particularly preferably 99.9% by mass or more.

Other subcomponents (components other than the main component) generally exemplified are dopants or co-solvents doped during the growth of the single crystal, and are produced in ceramics. A sintering aid or the like added at the time.

The method for producing the magnetic optical material of the present invention includes a single crystal production method such as a floating zone method or a micro-downdraw method, and a ceramic production method, and any method can be used. However, in general, in the single crystal production method, the design of the concentration ratio of the solid solution has a certain degree of limitation, and therefore, in the present invention, the ceramic production method is preferred.

Hereinafter, the ceramic production method which is an example of the method for producing a magnetic optical material of the present invention will be described in further detail, but the single crystal production method according to the technical idea of the present invention is not excluded.

<<Ceramic manufacturing method>> [raw material]

As the raw material used in the present invention, at least one element selected from the group consisting of ruthenium and element R (R-based lanthanum, cerium, titanium, lanthanum, tin, cerium, and zirconium) can be suitably used (however, In addition, the metal powder obtained by the constituent elements of the magnetic optical material of the present invention, which is composed of the element (), or an aqueous solution of nitric acid, sulfuric acid, uric acid or the like, or an oxide powder of the above element, etc., is excluded. .

These are quantitatively weighed so that the molar ratio of 鋱 to R becomes x:(2-x) (however, x is more than 0.800 and less than 1.00), and after mixing, baking is performed, and the desired result is obtained. A cubic crystal of pyrochlore-type oxide is used as a raw material for firing. For example, it is preferred to use at least one oxide powder selected from the group consisting of ruthenium, osmium, titanium, iridium, tin, bismuth, and zirconium (in the case of ruthenium, osmium, and iridium, excluding individual For the elemental oxide, the molar ratio of the atom of at least one R selected from the group consisting of ruthenium, osmium, titanium, ruthenium, tin, osmium, and zirconium is x: (2) -x) (however, x is more than 0.800 and less than 1.00), weigh and mix, and then fire in a crucible. In this case, in the case where a plurality of oxide powders of the plurality of elements R are selected from the group consisting of ruthenium, rhodium, titanium, iridium, tin, iridium, and zirconium, it is preferred that the molar ratio of the R atoms be such Weighing is carried out in a manner that is equally divided. For example, in the case of selecting two kinds of oxide powders of the elements R ₁ and R ₂ , it is preferable to measure the molar ratio of R ₁ :R _{2 to} 1:1.

The firing temperature at this time is preferably 1200 ° C or higher, and is a temperature lower than the sintering temperature to be performed thereafter, more preferably 1400 ° C or higher, and a temperature lower than the sintering temperature to be performed thereafter.

In addition, the term "main component" as used herein means that most of the calcination raw material (for example, a volume ratio of 50% or more) is occupied by an oxide of a pyrochlore crystal structure. In addition, the case where the calcination rate calculated from the powder X-ray diffraction result of the calcination raw material is 45.5% or more in the case where R in the above formula (1) is zirconium alone, and R is another case (that is, , R is at least one element selected from the group consisting of ruthenium, osmium, titanium, iridium, tin, antimony, and zirconium (however, in the case of yttrium, yttrium, and yttrium, the element is excluded) More than 50%, preferably more than 55%.

Further, the purity of the above raw material is preferably 99.9% by mass or more. Next, the obtained baking raw material is pulverized and used as a raw material powder.

In addition, the pyrochlore type oxygen of the desired composition is finally used. The powder is produced by ceramics. However, the shape of the powder at this time is not particularly limited, and for example, an angular, spherical or plate-shaped powder can be suitably used. In addition, even if it is a secondary-aggregated powder, it can be used suitably, and even if it is a granular powder granulated by the granulation process of the ink-jet drying process, etc., it can use suitably. Further, the preparation step of the raw material powders is not particularly limited. A raw material powder produced by a coprecipitation method, a pulverization method, a spray pyrolysis method, a sol-gel method, an alkoxide hydrolysis method, a complex polymerization method, or all other synthesis methods can be suitably used. Further, the obtained raw material powder may be suitably treated by a wet ball mill, a bead mill, a jet mill or a dry jet mill, a hammer mill or the like.

A sintering inhibition aid (sintering aid) may be appropriately added to the pyrochlore type oxide powder raw material used in the present invention. In particular, it is preferred to add a sintering inhibiting aid suitable for the pyrochlore-containing oxide containing cerium in order to obtain high transparency. However, the purity thereof is preferably 99.9% by mass or more. Further, in the case where the sintering inhibiting aid is not added, it is preferred that the raw material powder to be used be one in which the primary particle diameter is in the nanometer order and the sintering activity is extremely high. This choice is appropriate.

Further, various organic additives may be added for the purpose of improving the quality stability or the yield in the production step. In the present invention, there is no particular limitation on these. That is, various dispersants, binders, lubricants, plasticizers, and the like can be suitably used.

[manufacturing steps]

In the present invention, the raw material powder is used to pressurize to form a predetermined shape. After the form, degreasing is carried out, followed by sintering to prepare a densified sintered body having a relative density of at least 95% or more. As a subsequent step, it is preferred to carry out a heat-to-pressure (HIP) treatment.

(forming)

In the production method of the present invention, a usual press forming step can be suitably employed. In other words, a CIP (Cold Isostatic Pressing) step in which a raw material powder is filled in a mold and pressurized in a certain direction, or a CIP (Cold Isostatic Pressing) step which is hermetically stored in a deformable waterproof container and pressurized with hydrostatic pressure can be used. . In addition, the pressure is not particularly limited as long as the relative density of the obtained molded body is confirmed, and it can be managed by, for example, a commercially available CIP device having a pressure range of about 300 MPa or less. Suppress manufacturing costs. Alternatively, a hot pressing step, a discharge plasma sintering step, a microwave heating step, or the like which is carried out not only in the forming step but also in a single step until sintering can be suitably used. Further, not only the press molding method, but also a casting molding method in which a raw material powder is dispersed in water and an organic solvent and is poured into a mold to perform molding can be suitably used. The method of casting molding is not particularly limited, and a pressure casting method, a reduced pressure casting method, a solid casting method, a centrifugal casting method, or the like can be suitably used. In this case, a dispersing agent and a binder which are intended to improve the fluidity of the slurry or the shape retention of the molded body may be appropriately added.

(degreased)

In the manufacturing method of the present invention, the usual degreasing step can be suitably utilized. Step. That is, it can be subjected to a temperature rising degreasing step by a heating furnace. Further, the type of the ambient gas at this time is not particularly limited, and air, oxygen, hydrogen, or the like can be suitably used. The degreasing temperature is also not particularly limited. However, when a raw material of a mixed organic additive is used, it is preferred to raise the temperature until the organic component is decomposed and eliminated.

(sintering)

In the production method of the present invention, a general sintering step can be suitably employed. That is, a heating and sintering step of a resistance heating method or an induction heating method can be suitably employed. The environment at this time is not particularly limited, but an inert gas, oxygen, hydrogen, or the like can be suitably used. Further, sintering can be carried out under reduced pressure (in a vacuum).

The sintering temperature in the sintering step of the present invention is suitably adjusted by the selected starting materials. In general, the selected starting materials are used, and it is suitably selected to have a temperature of from 10 ° C to 100 ° C or about 200 ° C on the low temperature side of the melting point of the pyrochlore-type oxide sintered body containing the niobium. . In addition, when it is desired to produce a pyrochlore-type oxide sintered body containing a temperature range in which a phase other than the crystal lattice is changed in the vicinity of the selected temperature, it is strictly to avoid the temperature range. The management and sintering of the conditions can suppress the incorporation of phases other than cubic crystals, and have the advantage of reducing scattering of birefringence.

The sintering retention time in the sintering step of the present invention is appropriately adjusted depending on the selected starting materials. In general, most hours or so is sufficient. However, the relatively dense structure of the pyrochlore-type oxide sintered body containing bismuth The minimum degree must also be densified to more than 95%.

(hot room pressure equalization (HIP))

In the production method of the present invention, after the sintering step, a step of performing a hot isostatic pressing (HIP) treatment may be further added.

Further, in the case of the type of the pressurized gas medium at this time, an inert gas such as argon or nitrogen or Ar-O ₂ may be suitably used. The pressure for pressurizing by the pressurized gas medium is preferably from 50 to 300 MPa, more preferably from 100 to 300 MPa. When the pressure is less than 50 MPa, the effect of improving the transparency is not obtained. When the pressure exceeds 300 MPa, the transparency is not improved even if the pressure is increased, and the load on the device may be excessive and the device may be damaged. The pressure applied is preferably 196 MPa or less which can be handled by a commercially available HIP device, and is preferably simple.

In addition, the processing temperature (predetermined holding temperature) at this time may be appropriately set depending on the type of the material and/or the sintered state, and is set, for example, in the range of 1000 to 2000 ° C, preferably 1300 to 1800 ° C. In this case, in the same manner as in the case of the sintering step, it is necessary to set the melting point of the pyrochlore-type oxide containing the sintered body to be lower than the melting point and/or the phase transition point or less, and when the heat treatment temperature exceeds 2000 ° C, it is intended by the present invention. The sintered pyrochlore-type oxide sintered body may exceed the melting point or exceed the phase transition point, and it is difficult to perform an appropriate HIP treatment. Further, when the heat treatment temperature is less than 1000 ° C, the effect of improving the transparency of the sintered body cannot be obtained. In addition, there is no particular limitation on the holding time of the heat treatment temperature, but it is preferable to fully confirm The characteristics of the pyrochlore-type oxide constituting the sintered body are appropriately adjusted.

Further, the heating material, the heat insulating material, and the processing container for the HIP treatment are not particularly limited, but graphite, molybdenum (Mo), or tungsten (W) can be suitably used.

(annealing)

In the production method of the present invention, after the HIP treatment is completed, an oxygen deficiency is generated in the obtained pyrochlore-type oxide sintered body containing ruthenium, and a pale gray appearance is exhibited. In this case, it is preferred to apply a micro-oxidation annealing treatment under the same conditions as the aforementioned HIP treatment pressure, for example, at a temperature below the HIP treatment temperature (for example, 1100 to 1500 ° C). In this case, if the micro-oxidation annealing treatment is performed using the same equipment as the HIP processing apparatus described above, the manufacturing process is simple and preferable. By this annealing treatment, the bismuth-containing pyrochlore-type oxide sintered body exhibiting a pale gray appearance can also be adjusted to a completely colorless and transparent ceramic body.

(optical grinding)

In the manufacturing step of the present invention, it is preferable to use the yttrium-containing pyrochlore-type oxide sintered body (that is, transparent ceramic) which has undergone the above-described series of manufacturing steps, and optically utilize the two on the shaft. The end face is optically ground. The optical surface accuracy at this time is in the case of the measurement wavelength λ = 633 nm, preferably λ/8 or less, and particularly preferably λ/10 or less. In addition, it is also possible to further reduce the light by appropriately forming an anti-reflection film on the surface after optical polishing. Learn the loss.

As described above, a magnetic optical material in which the occurrence of a thermal lens is suppressed can be obtained. Further, in the magnetic optical material of the present invention, when laser light having a wavelength of 1064 nm is incident at a beam diameter of 1.6 mm as a light path length of 10 mm, it is preferable that the maximum value of the incident power of the laser light which does not generate the thermal lens is 30 W or more. More preferably 80W or more. When the maximum value of the incident power of the laser light in which the thermal lens does not occur is less than 30 W, it may be difficult to use the high-output optical fiber laser device. Further, the magnetic optical material of the present invention preferably has a linear transmittance of 90% or more of light having a wavelength of 1064 nm per 10 mm of the optical path length. In the present invention, the "linear transmittance" means an in-line transmittance when the transmission spectrum measured in a blank (space) state is not placed in the measurement light path and is 100%.

[Magnetic Optical Device]

The magnetic optical material of the present invention is suitable for use in a magnetic optical device, and is particularly preferably a Faraday rotator which is an optical isolator having a wavelength of 0.9 to 1.1 μm.

Fig. 1 is a schematic cross-sectional view showing an example of an optical isolator having an optical device in which a Faraday rotator composed of the magnetic optical material of the present invention is used as an optical element. In the first embodiment, the optical isolator 100 is provided with a Faraday rotator 110 composed of the magnetic optical material of the present invention, and a polarizing mirror 120 and an analyzer 130 as polarizing materials are provided in front of and behind the Faraday rotator 110. Moreover, the optical isolator 100 is preferably a polarizer 120, a farad The first rotor 110 and the analyzer 130 are arranged in this order, and the magnet 140 is placed on at least one of the side faces.

Further, the above-described optical isolator 100 can be suitably used for an industrial optical fiber laser device. That is, it is suitable for returning the reflected light from the laser light emitted from the laser light source to the light source, and preventing the oscillation from becoming unstable.

[Examples]

Hereinafter, the present invention will be more specifically described by way of examples, comparative examples and reference examples, but the present invention is not limited to the following examples.

[Example 1, Comparative Example 1, Reference Example 1]

In the above formula (1), an example in which yttrium, tin, and titanium are selected as a case where a single element is filled in the B site position (R in the above formula (1)) and x is changed will be described.

A cerium oxide powder manufactured by Shin-Etsu Chemical Co., Ltd., a cerium oxide powder manufactured by Alfa Aesar, and a tin dioxide powder and a titanium oxide powder manufactured by a high-purity chemical research institute. The purity was 99.9% by mass or more.

Using the above-mentioned raw materials, a total of 13 kinds of mixed oxide raw materials (1 type × 7 level + 2 types × 3 levels) which are a mixture ratio of the final composition as shown in Table 1 were produced. In other words, the mixed powder is prepared so that the molar number of the moles and the number of moles of the crucibles are x=0.700, 0.800, 0.900, 0.950, 0.990, 0.999, and 1.00, and the number of moles of the crucible is adjusted. The mixed powder is weighed in such a manner that the number of moles of tin or titanium becomes x = 0.700, 0.900, and 1.00 (that is, as Tb _1.40 Hf _2.60 O _7.30 , Tb _1.60 Hf _2.40 O _7.20 , Tb _1.80 Hf _2.20 O _7.10 , Tb _1.90 Hf _2.10 O _7.05 , Tb _1.98 Hf _2.02 O _7.01 , Tb _1.998 Hf _2.002 O _7.001 , Tb _2.00 Hf _2.00 O _7.00 , Tb _1.40 Sn _2.60 O _7.30 , Tb _1.80 Sn _2.20 O _7.10 , Tb _2.00 Sn _2.00 O _7.00 , Tb _1.40 Ti _2.60 O _7.30 , Tb _1.80 Ti _2.20 O _7.10 , Tb _2.00 Ti _2.00 O _7.00 mixed powder). Specifically, a mixed powder in which cerium oxide and cerium oxide are mixed so that cerium and lanthanum are respectively suitable molar ratios, and cerium oxide and tin dioxide are prepared so that cerium and tin respectively become suitable molar ratios Thirteen kinds of mixed powders were weighed and weighed, and cerium oxide and titanium oxide were weighed so that cerium and titanium became suitable molar ratios, respectively. Next, the dispersion/mixing treatment was carried out in a zirconia ball mill apparatus in ethanol while taking care to prevent each of them from entering each other. The processing time is 24 hours. Thereafter, a spray drying treatment was carried out to prepare a pelletized material having an average particle diameter of 20 μm.

Then, these powders were placed in a crucible, and subjected to a calcination treatment at a high temperature muffle furnace at 1400 ° C for 3 hours to obtain a calcined raw material of each composition. Each of the obtained calcined raw materials was subjected to diffraction pattern analysis by a powder X-ray diffraction apparatus manufactured by PANalytical Co., Ltd. The peak value of the sample is specified to the crystal system of the sample. When the peak is split by the influence of Cu-K α 1 ray and Cu-K α 2 ray, the case where a single crystal system cannot be determined is judged to be a mixed crystal. In addition, in the case of discussing the quality of magnetic optical materials, the case of non-single crystal system is sufficient to judge the mixed crystal, but here is the comparison with the reference data of the X-ray diffraction pattern or Ritvo. Analysis, and the crystal phase of the pyrochlore-type oxide is The outer phase is specific.

As a result, seven kinds of calcined raw materials of Hf (i.e., R = Hf) were used in the B site (Tb _1.40 Hf _2.60 O _7.30 , Tb _1.60 Hf _2.40 O _7.20 , Tb _1.80 Hf _2.20 O _7.10 , Tb _1.90 Hf _2.10 O _7.05 Tb _1.98 Hf _2.02 O _7.01 , Tb _1.998 Hf _2.002 O _7.001 , Tb _2.00 Hf _2.00 O _7.00 ) A cubic crystal which is presumably a crystal phase of a pyrochlore type oxide or a fluorite type oxide was confirmed. However, for Tb _1.60 Hf _2.40 O _7.20 and Tb _1.40 Hf _2.60 O _7.30 , a plurality of cubic fluorite-type oxides having different lattice constants are mixed.

Similarly, three types of firing materials (Tb _1.40 Sn _2.60 O _7.30 , Tb _1.80 Sn _2.20 O _7.10 , Tb _2.00 Sn _2.00 O _7.00 ) using Sn (i.e., R = Sn) in the B portion are all confirmed. It is presumed to be a cubic crystal of a crystal phase of a pyrochlore-type oxide. However, for Tb _1.40 Sn _2.60 O _7.30, it was confirmed that XRD diffraction peaks of other crystal phases were mixed in addition to the cubic pyrochlore type oxide, but the reference data was lacking and could not be specified.

Finally, three kinds of calcined raw materials (Tb _1.40 Ti _2.60 O _7.30 , Tb _1.80 Ti _2.20 O _7.10 , Tb _2.00 Ti _2.00 O _7.00 ) using Ti (i.e., R = Ti) at the B site were all confirmed to be presumable. It is a cubic crystal of a crystal phase of a pyrochlore-type oxide. However, for the Tb _1.40 Ti _2.60 O _7.30 series, in addition to the cubic pyrochlore type oxide, the XRD diffraction peak of the cubic fluorite-type oxide phase or the hexagonal crystal having different lattice constants is also mixed.

Each of the raw materials thus obtained was subjected to hydrostatic pressure treatment under uniaxial pressure molding and a pressure of 198 MPa to obtain a CIP molded body. The obtained molded body was subjected to degreasing treatment in a muffle furnace at 1000 ° C for 2 hours. Next, the dried molded body was placed in a vacuum heating furnace, and treated under a reduced pressure of 2.0 × 10 ^-3 Pa or less at 1700 ° C ± 20 ° C for 3 hours to obtain a total of 13 kinds (1 type × 7 level + Two kinds of sintered bodies of ×3 level). At this time, the sintering temperature was finely adjusted so that the sintered relative density of all the samples became 95%.

Each of the obtained sintered bodies was placed in a carbon heater HIP furnace, and subjected to HIP treatment in Ar, at 200 MPa, 1650 ° C, and for 3 hours.

Further, as a comparative example, a Tb _1.2 Y _0.8 O ₃ translucent ceramic (Comparative Example 1-5) was produced by referring to JP-A-2010-285299 (Patent Document 3).

Further, each of the ceramic sintered bodies obtained in this manner was subjected to grinding and polishing treatment so as to have a diameter of 5 mm and a length of 10 mm, and then the optical both end faces of the respective samples were optical surface precision λ/8 (at the measurement wavelength λ = 633 nm). Case) Final optical polishing.

Five kinds of ceramic sintered bodies of R = Hf and x = 0.700, 0.800, 0.900, 0.950, and 1.00 (that is, Tb _1.40 Hf _2.60 O _7.30 , Tb _1.60 Hf _2.40 O _7.20 , Tb _1.80 Hf _2.20 O _7.10 , Tb _1.90 Hf _2.10 O _7.05 and Tb _2.00 Hf _2.00 O _7.00 ), and a diffraction pattern (Fig. 2) was measured by an Out-of-plane XRD method using a powder X-ray diffraction apparatus (Smart Lab) manufactured by Rigaku. At this time, as the XRD condition, copper was generated at the anode, and X-rays were generated at 45 kV and 200 mA, and the scanning range was set to 10 to 110°. The reflection intensity of each ceramic sintered body was normalized by reflection at a range of 2 θ = 30° (that is, reflection on a pyrochlore-based (222) surface and reflection on a fluorite-based (111) surface). When x=1.00, the reflection of the (111) plane attributed to the cubic pyrochlore structure was observed in the vicinity of 2θ=14.6° (Fig. 3). With the decrease in x, the reflection intensity of the (111) plane observed in the vicinity of 2 θ = 14.6° is reduced. When x=0.800 and 0.700, the reflection near 2θ=14.6° is eliminated, and therefore, it is judged to be a diffraction pattern attributed to the cubic fluorite structure. Further, when x=0.800 and 0.700, the reflection (peak pattern) on the high-angle side is shunted by influences other than Cu-K α 1 ray and Cu-K α 2 ray, so it is judged that it belongs to the mixed crystal (4th) Figure).

For all of the 14 kinds of optically polished samples, the coating was designed to have an antireflection film having a center wavelength of 1064 nm. The optical appearance of the sample obtained here was also confirmed.

The linear transmittance of the obtained ceramic sample was measured as follows. Further, as shown in Fig. 1, a polarizing element was placed before and after each of the obtained ceramic samples, and the sample was inserted into the center of a 钕-iron-boron magnet having an outer diameter of 32 mm, an inner diameter of 6 mm, and a length of 40 mm, and then used. IPG Photonics Japan (high-power laser) (beam diameter 1.6mm), from the two end faces, the high-power laser light with a wavelength of 1064nm is incident, and the maximum value of the arcing constant and the incident power of the thermal lens are not measured.

(Method for measuring linear transmittance)

The linear transmittance is obtained by using a light source made by NKT Photonics, a power meter made by Gentec, and an optical system made of a Ge photodetector. The light having a wavelength of 1064 nm is used as a beam diameter of 1 to 3 mm. The size of the sample was measured by the light intensity at the time of passing through the sample (ceramic sample), and was determined according to the following formula in accordance with JIS K7361 and JIS K7136.

Linear transmittance (%/cm)=I/Io×100 (wherein I represents the transmitted light intensity (light intensity of a sample having a linear transmission length of 10 mm (1 cm)), and I ₀ represents incident light intensity).

For the sample having a linear transmittance of 80% or more, the following cutting constant and the maximum value of the incident power of the thermal lens are not measured, and the sample having a linear transmittance of less than 80% is not subjected to the cutting constant and does not occur. The measurement of the maximum value of the incident power of the thermal lens (hereinafter, the same applies to other embodiments).

(Method for measuring the reduction constant)

The cutting constant V is obtained by the following formula. Further, the magnitude (H) of the magnetic field applied to the sample is a value calculated by simulation from the dimensions of the measurement system, the residual magnetic flux density (Br), and the retention force (Hc).

θ=V×H×L (where θ is the Faraday rotation angle (min), V is the cutting constant, H is the magnitude of the magnetic field (Oe), and L is the length of the Faraday rotator (in this case, 1 cm)).

In addition, the cutting constant of Tb _1.2 Y _0.8 O ₃ of Comparative Example 1-5 is a reference value (Japanese Laid-Open Patent Publication No. 2010-285299 (Patent Document 3)).

(Method for measuring the maximum value of the incident power of the thermal lens)

First, a high-power laser light having a wavelength of 1,064 nm was emitted as a spatial light having a beam diameter of 1.6 mm in a state where the ceramic sample was not disposed, and the beam waist position F0 (m) was measured by a beam analyzer. Thereafter, a measurement sample (ceramic sample) was placed in the space optical system, and the beam waist position F1 (m) of the emitted light was measured in the same manner. The amount of change (ΔF) of the beam waist position at this time is expressed by the following expression.

△F(m)=F0-F1

At this time, the change of ΔF becomes larger as the input laser power increases, but the maximum incident laser power [W] when ΔF=0.1 m or less is used as the value of the negligible thermal lens (does not occur). The maximum value of the incident power of the thermal lens is obtained.

In addition, since the power laser system used has a maximum output of 100 W, the above thermal lens evaluation system cannot be performed.

The above results are all shown in Table 1.

From the above results, it was confirmed that the maximum value of the incident power of the Tb _1.2 Y _0.8 O ₃ system of Comparative Example 1-5 in which the thermal lens does not occur is 20 W, whereas in the above formula (1), the example of x = 0.900 1-4, 1-5, and 1-6 are excellent in transparency, and a magnetic optical material having a maximum value of incident power of a thermal lens of 100 W or more can be produced. Further, it was confirmed that Examples 1-1, 1-2, and 1-3 of x=0.999, 0.990, and 0.950 are excellent in transparency, and magnetic properties in which the maximum value of the incident power of the thermal lens does not occur is 100 W or more. Optical material. Further, in Reference Examples 1-1, 1-2, and 1-3 of x = 1.00, the maximum value of the incident power of the thermal lens does not occur is 80 W or 90 W, and in this embodiment, the incident power of the thermal lens does not occur. The maximum value is further improved to 100W or more. Further, in Comparative Example 1-1 of x=0.800 and Comparative Examples 1-2, 1-3, and 1-4 of x=0.700, all of them were mixed crystals and devitrified.

That is, it was confirmed that according to the present embodiment, a magnetic optical material in which the maximum value of the incident power of the thermal lens does not occur is 100 W or more can be produced.

[Example 2, Comparative Example 2, Reference Example 2]

In the above formula (1), an example in which a zirconium single element is selected as the B site position (R in the above formula (1)) and x is changed will be described.

A cerium oxide powder manufactured by Shin-Etsu Chemical Co., Ltd. and a zirconia powder manufactured by Nissan Chemical Industries Co., Ltd. were obtained. The purity was 99.9% by mass or more. Using the above raw materials, three kinds of oxide raw materials of x=0.700, 0.900, and 1.00 were produced (that is, Tb _1.40 Zr _2.60 O _7.30 , Tb _1.80 Zr _2.20 O _7.10 , Tb _2.00 Zr _2.00 O _7.00 ). Specifically, it is prepared to mix three kinds of mixed powders of cerium oxide and zirconium oxide so that cerium and zirconium each become a suitable molar ratio. Next, the dispersion/mixing treatment was carried out in a zirconia ball mill apparatus in ethanol while taking care to prevent each of them from entering each other. The processing time is 24 hours. Thereafter, a spray drying treatment was carried out to prepare a pelletized material having an average particle diameter of 20 μm.

Next, these powders were placed in a crucible, and subjected to a calcination treatment at a high temperature muffle furnace at 1300 ° C for 3 hours to obtain a calcined raw material of each composition. Each of the obtained calcined raw materials was subjected to diffraction pattern analysis by a powder X-ray diffraction apparatus manufactured by PANalytical Co., Ltd. The peak value of the sample is specified to the crystal system of the sample. When the peak is shunted due to influences other than Cu-K α 1 ray and Cu-K α 2 ray, it cannot be determined. The case of determining a single crystal system is judged to be a mixed crystal. In addition, in the case of discussing the quality of magnetic optical materials, the case of non-single crystal system is sufficient to judge the mixed crystal, but here is the comparison with the reference data of the X-ray diffraction pattern or Ritvo. In addition, the phases other than the crystal phase of the pyrochlore-type oxide are specified.

As a result, three types of calcined raw materials (Tb _1.40 Zr _2.60 O _7.30 , Tb _1.80 Zr _2.20 O _7.10 , Tb _2.00 Zr _2.00 O _7.00 ) using Zr (that is, R = Zr) at the B site were confirmed to be in addition to cubic crystals. A cubic fluorite-type oxide phase having a different lattice constant is also present in addition to the phase of the pyrochlore-type oxide.

Each of the raw materials thus obtained was subjected to hydrostatic pressure treatment under uniaxial pressure molding and a pressure of 198 MPa to obtain a CIP molded body. The obtained molded body was subjected to degreasing treatment in a muffle furnace at 1000 ° C for 2 hours. Then, the dried molded product was placed in a vacuum heating furnace, and treated at 1700 ° C ± 20 ° C for 3 hours under a reduced pressure of 2.0 × 10 ^-3 Pa or less to obtain a total of three kinds of sintered bodies. At this time, the sintering temperature was finely adjusted so that the sintered relative density of all the samples became 95%.

Each of the obtained sintered bodies was placed in a carbon heater HIP furnace, and subjected to HIP treatment in Ar, at 200 MPa, 1650 ° C, and for 3 hours.

Further, each of the ceramic sintered bodies obtained in this manner was subjected to grinding and polishing treatment in the same manner as in Example 1 to have a length of 10 mm, and then an antireflection film was applied.

The linear transmittance of the ceramic sample obtained in the same manner as in Example 1 was measured, and as shown in Fig. 1, the polarizing element was set at Each of the obtained ceramic samples was covered with a magnet before and after, and a high-power laser (beam diameter of 1.6 mm) made of IPG Photonics Japan was used, and high-power laser light having a wavelength of 1064 nm was incident from both end faces, and the same example. 1 The same method is used to determine the cutting constant and the maximum value of the incident power of the thermal lens.

The above results are shown in Table 2.

From the above results, it was confirmed that in the above-described formula (1), in Reference Example 2-1 where x = 1.00, the maximum value of the incident power of the thermal lens was 20 W, and the transparency of Example 2-1 was x = 0.900. Excellent, and it is possible to produce a magnetic optical material which is further improved to a maximum of 30 W after the incident power of the thermal lens does not occur. Further, in Example 2-1 and Reference Example 2-1, although the optical appearance was colorless and transparent, some birefringence occurred. Further, in Comparative Example 2-1 in which x = 0.700, the crystal was mixed and devitrified.

That is, it was confirmed that according to the present embodiment, a magnetic optical material in which the maximum value of the incident power of the thermal lens does not occur is 30 W can be produced.

[Example 3, Comparative Example 3]

In the above formula (1), x=0.900 is selected, and at least one of the group consisting of yttrium, lanthanum, titanium, lanthanum, and tin is selected in a group other than the composition of the first embodiment. The example is explained.

Acquired cerium oxide powder manufactured by Shin-Etsu Chemical Co., Ltd., and cerium oxide powder, cerium oxide powder, titanium oxide powder, tin dioxide powder, and Showa Chemical Co., Ltd. Tantalum pentoxide. The purity was 99.9% by mass or more.

Various raw oxide raw materials were produced using the above raw materials. That is, a mixed powder of cerium oxide and cerium oxide and zirconium oxide is prepared so that the molar ratio of cerium to cerium to zirconium becomes 1.80:1.10:1.10, and cerium oxide and cerium oxide and zirconium oxide are used. The mixed powder of 鋱 and 锗 and zirconium was made into a 1.80:1.10:1.10 method, and cerium oxide and tin dioxide and bismuth pentoxide were used to make the molar ratio of bismuth to tin to bismuth 1.80: In the method of 1.10:1.10, the mixed powder is weighed, and the mixed powder of cerium oxide is mixed with titanium oxide and lanthanum pentoxide to make the molar ratio of lanthanum to titanium and lanthanum 1.80:1.10:1.10. Weigh the mixed powder with cerium oxide in such a manner that the molar ratio of cerium to lanthanum is 1.80:2.20, and weigh cerium oxide and cerium oxide so that the molar ratio of cerium to lanthanum becomes 1.80:2.20. A mixed powder was weighed and mixed with cerium oxide and antimony pentoxide so that the molar ratio of cerium to lanthanum was 1.80:2.20. Next, the dispersion/mixing treatment was carried out in a zirconia ball mill apparatus in ethanol while taking care to prevent each of them from entering each other. The processing time is 24 hours. Then, put the powder into 铱坩 Thereafter, the firing treatment was carried out at a high temperature muffle furnace at 1400 ° C for 3 hours.

Next, the obtained various raw materials were again subjected to dispersion/mixing treatment in a zirconia ball mill apparatus in ethanol. The processing time is 40 hours. Thereafter, the spray drying treatment was again carried out to prepare a particulate composite oxide raw material having an average particle diameter of 20 μm.

Each of the raw materials thus obtained was subjected to hydrostatic pressure treatment under uniaxial pressure molding and a pressure of 198 MPa to obtain a CIP molded body. The obtained molded body was subjected to degreasing treatment in a muffle furnace at 1000 ° C for 2 hours. Next, the dried compact was placed in a vacuum heating furnace and treated at 1700 ° C ± 20 ° C for 3 hours to obtain various sintered bodies. At this time, the sintering temperature was finely adjusted so that the sintered relative density of all the samples became 95%.

Each of the obtained sintered bodies was placed in a carbon heater HIP furnace, and subjected to HIP treatment in Ar, at 200 MPa, 1650 ° C, and for 3 hours. A part of each of the obtained sintered bodies was pulverized by a zirconia mash to have a powder shape. Next, each of the powder samples obtained in the same manner as in Example 1 was subjected to diffraction pattern analysis by a powder X-ray diffraction apparatus manufactured by PANalytical Co., Ltd. As a result, it was confirmed that the composition of the cubic pyrochlore-type oxide was Tb _1.80 Si _1.10 Zr _1.10 O _7.10 , Tb _1.80 Ge _1.10 Zr _1.10 O _7.10 , Tb _1.80 Ti _1.10 Ta _1.10 O _7.10 , Tb _1.80 Sn _1.10 Ta _1.10 O _7.10 group. Further, although it is a pyrochlore type, the crystal system has an orthorhombic composition of Tb _1.80 Si _2.20 O _7.10 and Tb _1.80 Ge _2.20 O _7.10 . Finally, for the Tb _1.80 Ta _2.20 O _7.10 system, a clear pyrochlore-type diffraction pattern cannot be obtained, and a result of a mixed pattern of three different phases is obtained. However, it cannot be properly identified. Therefore, the expression is Tb _1.80 Ta _2.20 O _7.10+α .

The ceramic sintered bodies obtained in this manner were subjected to grinding and polishing treatment so as to have a length of 10 mm, and then the optical both end faces of the respective samples were subjected to optical surface precision λ/8 (at the measurement wavelength λ = 633 nm) for final optics. Grinding. Further, an antireflection film having a center wavelength of 1064 nm was applied by coating. The optical appearance of the sample obtained here was also confirmed.

The linear transmittance of the ceramic sample obtained in the same manner as in Example 1 was measured, and as shown in Fig. 1, the polarizing element was set to cover the magnet before and after the obtained ceramic sample, and IPG Photonics Japan was used. A high-power laser (beam diameter of 1.6 mm) was applied, and high-power laser light having a wavelength of 1064 nm was incident from both end faces, and the cutting constant was measured in the same manner as in Example 1 and the maximum incident power of the thermal lens was not generated. .

The results are summarized in Table 3.

From the above results, it was confirmed that even if the B site is filled with a single substance, it is devitrified or devitrified, and it is impossible to measure the element which does not cause the maximum value of the incident power of the thermal lens (specifically, Comparative Example 3-1 to 3) -3, 锗, 钽, 钽), in the case of a composition dissolved in the B site together with an appropriate third element (Examples 3-1 to 3-4), it will also become a pyrochlore type cube As the material of the main phase, the maximum value of the incident power of the thermal lens does not occur to be 40 W or more.

Further, the present invention has been described above by way of embodiments, but the present invention is not limited to the above-described embodiments, and other embodiments, additions, changes, deletions, and the like can be changed within the range that can be thought of by those skilled in the art. Any aspect of the present invention is included in the scope of the present invention as long as it exerts the effects of the present invention.

100‧‧‧Optical isolator

110‧‧‧Faraday rotor

120‧‧‧Polar mirror

130‧‧‧Analyzer

140‧‧‧ magnet

Claims (9)

A magnetic optical material comprising a transparent ceramic containing a composite oxide represented by the following formula (1) as a main component or a single crystal of a composite oxide represented by the following formula (1), Tb _2x R _2(2-x) O _8-x (1) (wherein 0.800 < x < 1.00, R is at least one selected from the group consisting of ruthenium, osmium, titanium, iridium, tin, iridium, and zirconium) Element (but, in the case of 矽, 锗, and 钽, excludes the element alone)). The magnetic optical material according to claim 1, wherein when the laser light having a wavelength of 1064 nm is incident at a beam diameter of 1.6 mm as the optical path length of 10 mm, the maximum value of the incident power of the laser light without the thermal lens is 30 W or more. The magnetic optical material according to claim 1 or 2, wherein the linear transmittance of light having a wavelength of 1064 nm per optical path of 10 mm is 90% or more. The magnetic optical material of claim 1 which is such that the cubic crystal having the pyrochlore crystal lattice becomes the main phase. A method for producing a magnetic optical material, which comprises at least one oxide powder selected from the group consisting of cerium oxide, lanthanum, titanium, cerium, tin, cerium, and zirconium (however, In the case of the cerium, the firing raw material containing the cubic pyrochlore-type oxide as a main component is produced by firing in the crucible, and the calcined raw material is pulverized as a raw material powder. After the raw material powder is formed into a predetermined shape, it is sintered, and further subjected to a heat-to-pressure equalization treatment to obtain a sintered body of a transparent ceramic containing a composite oxide represented by the following formula (1) as a main component, Tb _2x R _{2 (2-x} )O _8-x (1) (wherein 0.800<x<1.00, R is at least one element selected from the group consisting of ruthenium, osmium, titanium, iridium, tin, iridium, and zirconium ( However, in the case of 矽, 锗 and 钽, the exclusion is solely for this element)). The method for producing a magnetic optical material according to claim 5, wherein the cerium oxide powder and at least one oxide powder selected from the group consisting of cerium, lanthanum, titanium, lanthanum, tin, cerium, and zirconium are The molar ratio of at least one atom selected from the group consisting of ruthenium, rhodium, titanium, osmium, tin, iridium, and zirconium is x: (2-x) (however, the x system is greater than 0.800) After weighing and mixing in a manner of less than 1.00), the mixture is fired in a crucible. A magnetic optical device characterized by using the magnetic optical material according to any one of claims 1 to 4. The magnetic optical device according to claim 7, which is an optical isolator usable in a wavelength range of 0.9 μm or more and 1.1 μm or less, wherein the optical isolator comprises the above-mentioned magnetic optical material as a Faraday rotator, and the optical body of the Faraday rotator A polarizing material is provided on the front and rear of the shaft. The magnetic optical device of claim 8, wherein the Faraday rotator has an anti-reflection film on an optical surface thereof.