JP4432874B2

JP4432874B2 - Method for producing magnetic garnet single crystal

Info

Publication number: JP4432874B2
Application number: JP2005311682A
Authority: JP
Inventors: 敦大井戸
Original assignee: TDK Corp
Current assignee: TDK Corp
Priority date: 2005-10-26
Filing date: 2005-10-26
Publication date: 2010-03-17
Anticipated expiration: 2025-10-26
Also published as: JP2007119278A

Description

本発明は、フラックス法を用いて磁性ガーネット単結晶を育成する磁性ガーネット単結晶の製造方法に関する。 The present invention relates to a method for producing a magnetic garnet single crystal by growing a magnetic garnet single crystal using a flux method.

ファラデー回転子は、透過する光の偏光面を回転させる機能を有する光学素子であり、光アイソレータ、光アッテネータ、光磁界センサ等の光デバイスに使用される。ファラデー回転子は、一般に板状のビスマス（Ｂｉ）置換希土類鉄ガーネット単結晶を用いて作製される。Ｂｉ置換希土類鉄ガーネット単結晶は、フラックス法の一種である液相エピタキシャル（ＬＰＥ）法により育成される。 The Faraday rotator is an optical element having a function of rotating the plane of polarization of transmitted light, and is used in optical devices such as an optical isolator, an optical attenuator, and a magnetic field sensor. A Faraday rotator is generally manufactured using a plate-like bismuth (Bi) -substituted rare earth iron garnet single crystal. Bi-substituted rare earth iron garnet single crystal is grown by a liquid phase epitaxial (LPE) method which is a kind of flux method.

フラックス法等の溶液法によりＢｉ置換希土類鉄ガーネット単結晶を育成する際には、過飽和状態を保ちながらガーネット単結晶を安定に成長させるために、一般にＰｂＯ、Ｂｉ_２Ｏ_３及びＢ_２Ｏ_３が溶媒として用いられる。このため磁性ガーネット単結晶の育成時には結晶中に少量の鉛（Ｐｂ）が混入する。従来、通信用光デバイスに使用されるファラデー回転子には、化学式Ｂｉ_{３−α−β}Ｍ１_αＰｂ_βＦｅ_{５−γ−δ}Ｍ２_γＭ３_δＯ_１２においてＰｂの量βが０．０３〜０．０６程度である磁性ガーネット単結晶が用いられる。
特開２００１−０４４０２６号公報特開２００１−０４４０２７号公報 When a Bi-substituted rare earth iron garnet single crystal is grown by a solution method such as a flux method, PbO, Bi ₂ O ₃ and B ₂ O ₃ are generally used in order to stably grow a garnet single crystal while maintaining a supersaturated state. Used as a solvent. For this reason, when growing a magnetic garnet single crystal, a small amount of lead (Pb) is mixed in the crystal. Conventionally, the Faraday rotator used for the optical device for communication has a Pb amount β of 0.03 to 0 in the chemical formula Bi _3-α-β M1 _α Pb _β Fe _5-γ-δ M2 _γ M3 _δ O ₁₂ . A magnetic garnet single crystal of about .06 is used.
JP 2001-044026 A JP 2001-044027 A

ところが近年の環境保護運動の高まりと共に、全ての工業製品で環境負荷物質であるＰｂの含有量を削減する努力がなされている。従って、ＬＰＥ法により育成する磁性ガーネット単結晶においても、少量ではあるが混入するＰｂが環境汚染の要因になり得るとして問題になってきた。そこでファラデー回転子を構成する材料である磁性ガーネット単結晶に含有するＰｂの量を削減する必要が生じている。 However, with the recent increase in environmental protection movement, efforts are being made to reduce the content of Pb, which is an environmentally hazardous substance, in all industrial products. Therefore, even in a magnetic garnet single crystal grown by the LPE method, a small amount of Pb mixed therein has become a problem because it can cause environmental pollution. Therefore, it is necessary to reduce the amount of Pb contained in the magnetic garnet single crystal that is a material constituting the Faraday rotator.

本発明の目的は、Ｐｂの含有量を削減した磁性ガーネット単結晶の製造方法を提供することにある。 An object of the present invention is to provide a method for producing a magnetic garnet single crystal with a reduced Pb content.

上記目的は、Ｎａ、Ｂｉ及びＢを含む溶媒に、Ｆｅ、Ｇａ及びＡｌのうちＦｅを含む少なくとも一種の元素を９．０ｍｏｌ％以上２５．５ｍｏｌ％以下の配合率で溶解して溶液を生成し、前記溶液を用いて磁性ガーネット単結晶を育成することを特徴とする磁性ガーネット単結晶の製造方法によって達成される。 The purpose is to form a solution by dissolving at least one element containing Fe among Fe, Ga and Al in a solvent containing Na, Bi and B at a blending ratio of 9.0 mol% to 25.5 mol%. This is achieved by a method for producing a magnetic garnet single crystal using the solution to grow a magnetic garnet single crystal.

また上記目的は、Ｎａ、Ｂｉ及びＢを含む溶媒に、Ｆｅ、Ｇａ及びＡｌのうちＦｅを含む少なくとも一種の元素を溶解して溶液を生成し、前記溶液を用いて６００℃以上９００℃以下の育成温度で磁性ガーネット単結晶を育成することを特徴とする磁性ガーネット単結晶の製造方法によって達成される。 Further, the above object is to produce a solution by dissolving at least one element containing Fe among Fe, Ga and Al in a solvent containing Na, Bi and B, and using the solution, the temperature is from 600 ° C. to 900 ° C. This is achieved by a method for producing a magnetic garnet single crystal characterized by growing a magnetic garnet single crystal at a growth temperature.

さらに上記目的は、Ｎａ、Ｂｉ及びＢを含む溶媒に、Ｆｅ、Ｇａ及びＡｌのうちＦｅを含む少なくとも一種の元素を配合率ｘ（ｍｏｌ％）で溶解して溶液を生成し、前記溶液を用いて、４３６＋１８．２ｘ≦ｙ≦５５５＋１８．２ｘを満たす育成温度ｙ（℃）で磁性ガーネット単結晶を育成することを特徴とする磁性ガーネット単結晶の製造方法によって達成される。 Further, the object is to produce a solution by dissolving at least one element containing Fe among Fe, Ga and Al in a solvent containing Na, Bi and B at a compounding ratio x (mol%), and using the solution. The magnetic garnet single crystal is grown at a growth temperature y (° C.) that satisfies 436 + 18.2x ≦ y ≦ 555 + 18.2x.

上記本発明の磁性ガーネット単結晶の製造方法であって、前記配合率ｘは９．０ｍｏｌ％以上であり、前記育成温度ｙは９００℃以下であることを特徴とする。 In the method for producing a magnetic garnet single crystal of the present invention, the blending ratio x is 9.0 mol% or more, and the growth temperature y is 900 ° C. or less.

上記本発明の磁性ガーネット単結晶の製造方法であって、前記溶液はＡｕ製のルツボ内で生成することを特徴とする。 In the method for producing a magnetic garnet single crystal of the present invention, the solution is produced in a crucible made of Au.

本発明によれば、Ｐｂの含有量を削減した磁性ガーネット単結晶を実現できる。 According to the present invention, a magnetic garnet single crystal with reduced Pb content can be realized.

本発明の一実施の形態による磁性ガーネット単結晶の製造方法について図１乃至図３を用いて説明する。本実施の形態では、ガーネット単結晶に微量含まれていたＰｂを完全に除去するために、従来の溶媒に含まれるＰｂをナトリウム（Ｎａ）で代替し、Ｎａ、Ｂｉ及びホウ素（Ｂ）を含む溶媒からＢｉ置換希土類鉄ガーネット単結晶を育成する。ところが、Ｎａ、Ｂｉ及びＢを含む溶媒からガーネット単結晶を育成する技術は開発されて間もないため、ガーネット単結晶を安定に育成できる育成条件の詳細は明らかになっていない。特に、溶質の主成分であるＦｅ_２Ｏ_３、Ｇａ_２Ｏ_３及びＡｌ_２Ｏ_３に関する育成条件は分かっていない。そのため、育成条件によってはガーネット単結晶が得られないという問題や、欠陥や割れが多数あるガーネット単結晶しか得られないという問題が生じ得る。 A method for producing a magnetic garnet single crystal according to an embodiment of the present invention will be described with reference to FIGS. In this embodiment, in order to completely remove Pb contained in a trace amount in a garnet single crystal, Pb contained in a conventional solvent is replaced with sodium (Na), and Na, Bi, and boron (B) are contained. A Bi-substituted rare earth iron garnet single crystal is grown from a solvent. However, since a technique for growing a garnet single crystal from a solvent containing Na, Bi, and B has just been developed, details of growth conditions that can stably grow a garnet single crystal have not been clarified. In particular, the growth conditions for Fe ₂ O ₃ , Ga ₂ O ₃ and Al ₂ O ₃ which are the main components of the solute are not known. Therefore, depending on the growth conditions, there may be a problem that a garnet single crystal cannot be obtained, or a problem that only a garnet single crystal having many defects and cracks can be obtained.

本実施の形態では、Ｎａ、Ｂｉ及びＢを含む溶媒を用い、溶質の主成分である鉄（Ｆｅ）、ガリウム（Ｇａ）及びアルミニウム（Ａｌ）の配合率ｘを変えた種々の育成条件でＢｉ置換希土類鉄ガーネット単結晶（磁性ガーネット単結晶）の育成を試みた。ここで、本願明細書中で用いられる「配合率」とは、ルツボに充填されるＮａ、Ｂｉ、Ｂ、Ｆｅ、Ｇａ、Ａｌ、希土類元素など溶液中でカチオン（陽イオン）となる元素の総ｍｏｌ数に占める各元素のｍｏｌ数の割合（ｍｏｌ％）のことである。また、「Ｆｅ、Ｇａ及びＡｌの配合率ｘ」とは、Ｆｅの配合率、Ｇａの配合率及びＡｌの配合率の和のことである。図１は、Ｆｅ、Ｇａ及びＡｌの配合率ｘと、ガーネット単結晶を育成する際の溶液の温度（育成温度）ｙとの関係を示すグラフである。グラフの横軸は配合率ｘ（ｍｏｌ％）を表し、縦軸は育成温度ｙ（℃）を表している。 In the present embodiment, a solvent containing Na, Bi and B is used, and Bi is grown under various growth conditions in which the mixing ratio x of iron (Fe), gallium (Ga) and aluminum (Al), which are main components of the solute, is changed. Attempts were made to grow substituted rare earth iron garnet single crystals (magnetic garnet single crystals). Here, the “mixing ratio” used in the present specification is the total number of elements that become cations (cations) in a solution such as Na, Bi, B, Fe, Ga, Al, and rare earth elements filled in the crucible. It is the ratio (mol%) of the number of moles of each element in the number of moles. In addition, “Fe, Ga, and Al compounding ratio x” is the sum of Fe compounding ratio, Ga compounding ratio, and Al compounding ratio. FIG. 1 is a graph showing the relationship between the mixing ratio x of Fe, Ga and Al and the temperature (growth temperature) y of the solution when growing a garnet single crystal. The horizontal axis of the graph represents the blending ratio x (mol%), and the vertical axis represents the growth temperature y (° C.).

Ｎａ、Ｂｉ及びＢを含む溶媒からガーネット単結晶を育成する際には、金（Ａｕ）製のルツボが必須と考えられる。Ａｕは比較的低い融点（１０６４℃）を持つ柔らかい金属であるため、溶液の温度が９５０℃を超えるとＡｕ製ルツボは形状を保てなくなる。したがって、ルツボに投入した材料を融解する融解温度は９５０℃以下にする必要がある。ガーネット単結晶は融解温度より更に温度の低い過飽和状態で育成されることになるので、育成温度ｙは９００℃以下にする必要がある（図１の直線ａ及びそれより下）。Ｆｅ、Ｇａ及びＡｌの配合率ｘを変えて単結晶育成を行ったところ、育成温度ｙを９００℃以下にするにはＦｅ、Ｇａ及びＡｌの配合率ｘを２５．５ｍｏｌ％以下にする必要があることが分かった（図１の直線ｂ及びそれより左）。 When growing a garnet single crystal from a solvent containing Na, Bi and B, a crucible made of gold (Au) is considered essential. Since Au is a soft metal having a relatively low melting point (1064 ° C.), the shape of the Au crucible cannot be maintained when the temperature of the solution exceeds 950 ° C. Therefore, the melting temperature for melting the material charged in the crucible needs to be 950 ° C. or lower. Since the garnet single crystal is grown in a supersaturated state lower in temperature than the melting temperature, the growing temperature y needs to be 900 ° C. or lower (the straight line a in FIG. 1 and below). When single crystal growth was performed while changing the mixing ratio x of Fe, Ga and Al, it was necessary to set the mixing ratio x of Fe, Ga and Al to 25.5 mol% or less in order to make the growth temperature y 900 ° C. or less. It was found that there is a line (b in FIG. 1 and left).

一方、Ｆｅ、Ｇａ及びＡｌの配合率ｘを低くするとガーネット単結晶の成長速度が低下する。成長速度が著しく低下すると、ファラデー回転子に加工し得る大きさのガーネット単結晶を得るためには極めて長時間の結晶育成が必要となってしまい、ガーネット単結晶を製造する上で障害となる。具体的には、Ｆｅ、Ｇａ及びＡｌの配合率ｘが９．０ｍｏｌ％より低くなると、成長速度が低くなり過ぎてファラデー回転子に適したガーネット単結晶の育成が困難になる。したがって、Ｆｅ、Ｇａ及びＡｌの配合率ｘは９．０ｍｏｌ％以上であることが望ましい（図１の直線ｃ及びそれより右）。また、Ｆｅ、Ｇａ及びＡｌの配合率ｘを９．０ｍｏｌ％以上にするには、育成温度ｙを６００℃以上にする必要があることが分かった（図１の直線ｄ及びそれより上）。 On the other hand, when the mixing ratio x of Fe, Ga and Al is lowered, the growth rate of the garnet single crystal is lowered. When the growth rate is remarkably reduced, crystal growth for an extremely long time is required to obtain a garnet single crystal having a size that can be processed into a Faraday rotator, which is an obstacle to producing a garnet single crystal. Specifically, when the blending ratio x of Fe, Ga, and Al is lower than 9.0 mol%, the growth rate becomes too low and it becomes difficult to grow a garnet single crystal suitable for a Faraday rotator. Therefore, the blending ratio x of Fe, Ga and Al is desirably 9.0 mol% or more (the straight line c in FIG. 1 and the right side thereof). Further, it was found that the growth temperature y must be 600 ° C. or higher in order to make the Fe, Ga, and Al compounding ratio x be 9.0 mol% or higher (straight line d in FIG. 1 and above).

Ｂｉ置換希土類鉄ガーネット（Ｂｉ_ｚＲｅ_３−ｚＦｅ_５Ｏ_１２；Ｒｅは希土類元素を表す）単結晶において十分に大きいファラデー回転角を得るためには、Ｂｉ量を示すｚが０．５以上であることが望ましい。一方、Ｂｉ量ｚが１．５より大きくなると過飽和状態が不安定になり、ガーネット単結晶に多数の割れや欠陥が発生してしまうため、Ｂｉ量ｚは１．５以下であることが望ましい。したがって、Ｂｉ置換希土類鉄ガーネット単結晶をファラデー回転子に用いるためには、Ｂｉ量ｚは０．５以上１．５以下であるのが望ましい。 Bi-substituted rare earth iron garnet _{_{_{_{(Bi z Re 3-z Fe}}}} 5 O 12; Re represents a rare earth element) in order to obtain a sufficiently large Faraday rotation angle in the single crystal, with z indicating the Bi content is 0.5 or more It is desirable to be. On the other hand, if the Bi amount z is larger than 1.5, the supersaturated state becomes unstable, and a large number of cracks and defects occur in the garnet single crystal. Therefore, the Bi amount z is desirably 1.5 or less. Therefore, in order to use a Bi-substituted rare earth iron garnet single crystal for a Faraday rotator, the Bi amount z is desirably 0.5 or more and 1.5 or less.

Ｂｉは希土類元素と比較して温度が低くなるほど偏析係数が大きくなるため、育成温度ｙが低くなるほどガーネット単結晶中のＢｉ量ｚは多くなる傾向がある。したがって、Ｆｅ、Ｇａ及びＡｌの配合率ｘが同じ材料を用いた場合、Ｂｉ量ｚの少ないガーネット単結晶を育成する際の育成温度ｙは高くなり、Ｂｉ量ｚの多いガーネット単結晶を育成する場合の育成温度ｙは低くなる傾向がある。 Since Bi has a higher segregation coefficient as the temperature is lower than that of rare earth elements, the Bi amount z in the garnet single crystal tends to increase as the growth temperature y decreases. Therefore, when materials having the same mixing ratio x of Fe, Ga, and Al are used, the growth temperature y when growing a garnet single crystal with a small Bi amount z is high, and a garnet single crystal with a large Bi amount z is grown. In this case, the growth temperature y tends to be low.

Ｆｅ、Ｇａ及びＡｌの配合率ｘを９．０ｍｏｌ％から１９．０ｍｏｌ％までの範囲で変えて、Ｂｉ量ｚが０．５のＢｉ置換希土類鉄ガーネット単結晶を育成した。配合率ｘと育成温度ｙとの間には、図１の直線ｅのようなほぼ直線的な関係が認められた。配合率ｘ（ｍｏｌ％）及び育成温度ｙ（℃）の関係は、単位の次元を無視するとｙ＝５５５＋１８．２ｘと表される。これは、Ｆｅ、Ｇａ及びＡｌの配合率ｘが増加すると材料の融解温度が直線的に上昇し、それに伴い育成温度ｙも上昇するためと考えられる。 A Bi-substituted rare earth iron garnet single crystal having a Bi content z of 0.5 was grown by changing the compounding ratio x of Fe, Ga and Al in a range from 9.0 mol% to 19.0 mol%. A substantially linear relationship such as a straight line e in FIG. 1 was recognized between the blending ratio x and the growth temperature y. The relationship between the blending ratio x (mol%) and the growth temperature y (° C.) is expressed as y = 555 + 18.2x when the unit dimension is ignored. This is presumably because the melting temperature of the material rises linearly and the growth temperature y rises along with an increase in the mixing ratio x of Fe, Ga and Al.

また、Ｆｅ、Ｇａ及びＡｌの配合率ｘを９．０ｍｏｌ％から２５．５ｍｏｌ％までの範囲で変えて、Ｂｉ量ｚが１．５のＢｉ置換希土類鉄ガーネット単結晶を育成した。配合率ｘと育成温度ｙとの間には、図１の直線ｅよりも低い育成温度ｙで直線ｅとほぼ同一の傾きを持つ直線ｆのような直線的な関係が認められた。配合率ｘ（ｍｏｌ％）及び育成温度ｙ（℃）の関係は、単位の次元を無視するとｙ＝４３６＋１８．２ｘと表される。したがって、２本の直線ｅ、ｆ及びそれらで挟まれた範囲の配合率ｘ及び育成温度ｙで単結晶を育成することにより、Ｂｉ量ｚが０．５以上１．５以下でありファラデー回転子に適したＢｉ置換希土類鉄ガーネット単結晶が得られることが分かった。 Further, a Bi-substituted rare earth iron garnet single crystal having a Bi content z of 1.5 was grown by changing the compounding ratio x of Fe, Ga, and Al in a range from 9.0 mol% to 25.5 mol%. A linear relationship such as a straight line f having almost the same inclination as the straight line e at a growing temperature y lower than the straight line e in FIG. 1 was recognized between the blending ratio x and the growing temperature y. The relationship between the compounding ratio x (mol%) and the growth temperature y (° C.) is expressed as y = 436 + 18.2x when the unit dimension is ignored. Therefore, by growing a single crystal with two straight lines e and f and a blending ratio x and a growth temperature y in a range between them, the Bi amount z is 0.5 to 1.5 and the Faraday rotator It was found that a Bi-substituted rare earth iron garnet single crystal suitable for the above can be obtained.

以上の結果より、Ｂｉ置換希土類鉄ガーネット単結晶の好ましい育成条件が得られた。すなわち、Ｆｅ、Ｇａ及びＡｌの配合率ｘが９．０ｍｏｌ％以上２５．５ｍｏｌ％以下である場合（図１の２本の直線ｃ、ｂ及びそれらの間）に、ファラデー回転子に適したＢｉ置換希土類鉄ガーネット単結晶を育成できる。また、育成温度ｙが６００℃以上９００℃以下である場合（図１の２本の直線ｄ、ａ及びそれらの間）に、ファラデー回転子に適したＢｉ置換希土類鉄ガーネット単結晶を育成できる。さらに、Ｆｅ、Ｇａ及びＡｌの配合率ｘ（ｍｏｌ％）と育成温度ｙ（℃）とが４３６＋１８．２ｘ≦ｙ≦５５５＋１８．２ｘの関係を満たす場合（図１の２本の直線ｆ、ｅ及びそれらの間）に、ファラデー回転子に適したＢｉ置換希土類鉄ガーネット単結晶を育成できる。図１の直線ａ、ｃ、ｅ、ｆ及びそれらで囲まれた範囲の配合率ｘ及び育成温度ｙのようにこれらの育成条件を全て満たすことによって、ファラデー回転子に適したＢｉ置換希土類鉄ガーネット単結晶をより安定に育成できるようになる。 From the above results, preferable growth conditions for Bi-substituted rare earth iron garnet single crystals were obtained. That is, when the mixing ratio x of Fe, Ga, and Al is 9.0 mol% or more and 25.5 mol% or less (two straight lines c and b in FIG. 1 and between them), Bi suitable for a Faraday rotator. A substituted rare earth iron garnet single crystal can be grown. Further, when the growth temperature y is 600 ° C. or more and 900 ° C. or less (the two straight lines d and a in FIG. 1 and between them), a Bi-substituted rare earth iron garnet single crystal suitable for a Faraday rotator can be grown. Further, when the mixing ratio x (mol%) of Fe, Ga and Al and the growth temperature y (° C.) satisfy the relationship of 436 + 18.2x ≦ y ≦ 555 + 18.2x (two straight lines f, e and Between them, Bi-substituted rare earth iron garnet single crystals suitable for Faraday rotators can be grown. A Bi-substituted rare earth iron garnet suitable for a Faraday rotator is obtained by satisfying all of these growth conditions such as the straight lines a, c, e, and f in FIG. A single crystal can be grown more stably.

なお本実施の形態では、溶媒に溶解する溶質の主成分としてＦｅ、Ｇａ及びＡｌを用いているが、Ｇａ及びＡｌは必ずしも用いる必要はない。例えばＧａを用いない場合、配合率ｘはＦｅの配合率とＡｌの配合率との和を表す。またＧａ及びＡｌの双方を用いない場合、配合率ｘはＦｅの配合率を表す。 In this embodiment, Fe, Ga, and Al are used as the main components of the solute dissolved in the solvent. However, Ga and Al are not necessarily used. For example, when Ga is not used, the blending ratio x represents the sum of the blending ratio of Fe and the blending ratio of Al. Moreover, when not using both Ga and Al, the compounding rate x represents the compounding rate of Fe.

本実施の形態によれば、Ｐｂの含有量を削減した磁性ガーネット単結晶の製造方法を実現できる。また本実施の形態によれば、Ｎａ、Ｂｉ及びＢを含む溶媒を用いてファラデー回転子に適したＢｉ置換希土類鉄ガーネット単結晶を安定に育成することが可能になる。
以下、本実施の形態による磁性ガーネット単結晶の製造方法について、実施例及び比較例を用いてより具体的に説明する。 According to the present embodiment, a method for producing a magnetic garnet single crystal with a reduced Pb content can be realized. Further, according to the present embodiment, it is possible to stably grow a Bi-substituted rare earth iron garnet single crystal suitable for a Faraday rotator using a solvent containing Na, Bi and B.
Hereinafter, the manufacturing method of the magnetic garnet single crystal by this Embodiment is demonstrated more concretely using an Example and a comparative example.

（実施例１）
図２は、単結晶を育成する工程の一部を示している。まずＡｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは１４．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．５ｍｏｌ％、５２．５ｍｏｌ％、２４．５ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９００℃まで炉温を上げてルツボ４内の材料を融解温度９００℃で融解して攪拌し、均一な融液（溶液）８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ（ガドリニウム・ガリウム・ガーネット）基板１０を固定冶具２に取り付けて炉内に投入した。７５０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度７５０℃でエピタキシャル成長を４時間行った。ｙ１＝４３６＋１８．２ｘ、ｙ２＝５５５＋１８．２ｘとすると、育成温度ｙとｙ１、ｙ２との関係はｙ１＜ｙ＜ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_１．００Ｇｄ_１．７０Ｙｂ_０．３０Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ（ＩｎｄｕｃｔｉｖｅｌｙＣｏｕｐｌｅｄＰｌａｓｍａ；高周波誘導結合プラズマ）分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄＹｂ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 Example 1
FIG. 2 shows a part of a process for growing a single crystal. First, in a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O, which weighs 2.3 kg in total. _3. Filled with NaOH. The blending ratio x of Fe, Ga and Al was 14.0 mol%. Moreover, the compounding ratio of B, Bi, and Na was 8.5 mol%, 52.5 mol%, and 24.5 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 900 ° C., and the material in the crucible 4 was melted at a melting temperature of 900 ° C. and stirred to produce a uniform melt (solution) 8. A CaMgZr-substituted GGG (gadolinium gallium garnet) substrate 10 having a diameter of 2 inches was attached to the fixed jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 750 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 750 ° C. for 4 hours. When y1 = 436 + 18.2x and y2 = 555 + 18.2x, the relationship between the growth temperature y and y1, y2 was y1 <y <y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. Composition analysis of the single crystal by X-ray fluorescence analysis revealed that the composition was Bi _1.00 Gd _1.70 Yb _0.30 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na could be detected However, the composition could not be determined. Next, when the composition was evaluated in detail by ICP (Inductively Coupled Plasma) analysis, the chemical formula of the magnetic garnet single crystal was (BiGdYb) _2.998 Na _0.002 (FeGaAl) _5.000 O ₁₂ . It was found that this was a Bi-substituted rare earth iron garnet single crystal that could be used for a Faraday rotator.

（実施例２）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは１４．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．４ｍｏｌ％、５２．４ｍｏｌ％、２４．４ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９００℃まで炉温を上げてルツボ４内の材料を融解温度９００℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。８１０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度８１０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１＜ｙ≒ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_０．５２Ｇｄ_２．４８Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 (Example 2)
The crucible 4 made of Au was filled with Gd ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O ₃ , and NaOH that totaled 2.3 kg. . The blending ratio x of Fe, Ga and Al was 14.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 8.4 mol%, 52.4 mol%, and 24.4 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 900 ° C., and the material in the crucible 4 was melted at a melting temperature of 900 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 810 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 810 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1 <y≈y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. The composition of the single crystal was analyzed by X-ray fluorescence analysis. The composition was Bi _0.52 Gd _2.48 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na was detected but the composition was confirmed. I couldn't. Next, when the composition was evaluated in detail by ICP analysis, it was found that the chemical formula of the magnetic garnet single crystal was (BiGd) _2.998 Na _0.002 (FeGaAl) _5.000 O ₁₂ and used for the Faraday rotator. It was confirmed that it was a possible Bi-substituted rare earth iron garnet single crystal.

（実施例３）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは１４．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．５ｍｏｌ％、５２．６ｍｏｌ％、２４．５ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９００℃まで炉温を上げてルツボ４内の材料を融解温度９００℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。６９０℃まで融液の温度を下げてから基板１０の片面を融液８に接触させ、育成温度６９０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１≒ｙ＜ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_１．５０Ｇｄ_０．８７Ｙｂ_０．６３Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄＹｂ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 (Example 3)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O _{3 that} weighs 2.3 kg in total. Charged with NaOH. The blending ratio x of Fe, Ga and Al was 14.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 8.5 mol%, 52.6 mol%, and 24.5 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 900 ° C., and the material in the crucible 4 was melted at a melting temperature of 900 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt was lowered to 690 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 690 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1≈y <y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. When the composition of the single crystal was analyzed by X-ray fluorescence analysis, the composition was Bi _1.50 Gd _0.87 Yb _0.63 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na could be detected. However, the composition could not be determined. Next, when the composition was evaluated in detail by ICP analysis, it was found that the chemical formula of the magnetic garnet single crystal was (BiGdYb) _2.998 Na _0.002 (FeGaAl) _5.000 O ₁₂ and used for the Faraday rotator. It was confirmed that it was a possible Bi-substituted rare earth iron garnet single crystal.

（実施例４）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは９．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．９ｍｏｌ％、５５．４ｍｏｌ％、２５．８ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９００℃まで炉温を上げてルツボ４内の材料を融解温度９００℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。７２０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度７２０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１＜ｙ≒ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_０．５２Ｇｄ_２．４８Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 Example 4
The crucible 4 made of Au was filled with Gd ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O ₃ , and NaOH that totaled 2.3 kg. . The blending ratio x of Fe, Ga and Al was 9.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 8.9 mol%, 55.4 mol%, and 25.8 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 900 ° C., and the material in the crucible 4 was melted at a melting temperature of 900 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 720 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 720 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1 <y≈y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. The composition of the single crystal was analyzed by X-ray fluorescence analysis. The composition was Bi _0.52 Gd _2.48 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na was detected but the composition was confirmed. I couldn't. Then composition was examined in detail by the ICP analysis, the chemical formula of the magnetic garnet single crystal _was found to be _{_{_{5.000 O 12 (BiGd) 2.998 Na}}} 0.002 (FeGaAl), used in the Faraday rotator It was confirmed that it was a possible Bi-substituted rare earth iron garnet single crystal.

（実施例５）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは９．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．９ｍｏｌ％、５５．５ｍｏｌ％、２５．９ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９００℃まで炉温を上げてルツボ４内の材料を融解温度９００℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。６６０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度６６０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１＜ｙ＜ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_１．００Ｇｄ_１．７０Ｙｂ_０．３０Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄＹｂ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 (Example 5)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O _{3 that} weighs 2.3 kg in total. Charged with NaOH. The blending ratio x of Fe, Ga and Al was 9.0 mol%. Moreover, the compounding rates of B, Bi, and Na were 8.9 mol%, 55.5 mol%, and 25.9 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 900 ° C., and the material in the crucible 4 was melted at a melting temperature of 900 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 660 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 660 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1 <y <y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. Composition analysis of the single crystal by X-ray fluorescence analysis revealed that the composition was Bi _1.00 Gd _1.70 Yb _0.30 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na could be detected However, the composition could not be determined. Next, when the composition was evaluated in detail by ICP analysis, it was found that the chemical formula of the magnetic garnet single crystal was (BiGdYb) _2.998 Na _0.002 (FeGaAl) _5.000 O ₁₂ and used for the Faraday rotator. It was confirmed that it was a possible Bi-substituted rare earth iron garnet single crystal.

（実施例６）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは９．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ９．０ｍｏｌ％、５５．６ｍｏｌ％、２５．９ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９００℃まで炉温を上げてルツボ４内の材料を融解温度９００℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。６００℃まで融液８の温度を下げてから基板１０の片面を融液に接触させ、育成温度６００℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１≒ｙ＜ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_１．５０Ｇｄ_０．８７Ｙｂ_０．６３Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄＹｂ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 (Example 6)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O _{3 that} weighs 2.3 kg in total. Charged with NaOH. The blending ratio x of Fe, Ga and Al was 9.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 9.0 mol%, 55.6 mol%, and 25.9 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 900 ° C., and the material in the crucible 4 was melted at a melting temperature of 900 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 600 ° C., one side of the substrate 10 was brought into contact with the melt, and epitaxial growth was performed at a growth temperature of 600 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1≈y <y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. When the composition of the single crystal was analyzed by X-ray fluorescence analysis, the composition was Bi _1.50 Gd _0.87 Yb _0.63 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na could be detected. However, the composition could not be determined. Next, when the composition was evaluated in detail by ICP analysis, it was found that the chemical formula of the magnetic garnet single crystal was (BiGdYb) _2.998 Na _0.002 (FeGaAl) _5.000 O ₁₂ and used for the Faraday rotator. It was confirmed that it was a possible Bi-substituted rare earth iron garnet single crystal.

（実施例７）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは１９．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．０ｍｏｌ％、４９．３ｍｏｌ％、２３．０ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９５０℃まで炉温を上げてルツボ４内の材料を融解温度９５０℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。９００℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度９００℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１＜ｙ≒ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_０．５２Ｇｄ_２．４８Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 (Example 7)
The crucible 4 made of Au was filled with Gd ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O ₃ , and NaOH that totaled 2.3 kg. . The compounding ratio x of Fe, Ga and Al was 19.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 8.0 mol%, 49.3 mol%, and 23.0 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 950 ° C., and the material in the crucible 4 was melted at a melting temperature of 950 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 900 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 900 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1 <y≈y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. The composition of the single crystal was analyzed by X-ray fluorescence analysis. The composition was Bi _0.52 Gd _2.48 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na was detected but the composition was confirmed. I couldn't. Next, when the composition was evaluated in detail by ICP analysis, it was found that the chemical formula of the magnetic garnet single crystal was (BiGd) _2.998 Na _0.002 (FeGaAl) _5.000 O ₁₂ and used for the Faraday rotator. It was confirmed that it was a possible Bi-substituted rare earth iron garnet single crystal.

（実施例８）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率は１９．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．０ｍｏｌ％、４９．４ｍｏｌ％、２３．０ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９５０℃まで炉温を上げてルツボ４内の材料を融解温度９５０℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。８４０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度８４０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１＜ｙ＜ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_１．００Ｇｄ_１．７０Ｙｂ_０．３０Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄＹｂ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 (Example 8)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O _{3 that} weighs 2.3 kg in total. Charged with NaOH. The compounding ratio of Fe, Ga, and Al was 19.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 8.0 mol%, 49.4 mol%, and 23.0 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 950 ° C., and the material in the crucible 4 was melted at a melting temperature of 950 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 840 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 840 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1 <y <y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. Composition analysis of the single crystal by X-ray fluorescence analysis revealed that the composition was Bi _1.00 Gd _1.70 Yb _0.30 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na could be detected However, the composition could not be determined. Next, when the composition was evaluated in detail by ICP analysis, it was found that the chemical formula of the magnetic garnet single crystal was (BiGdYb) _2.998 Na _0.002 (FeGaAl) _5.000 O ₁₂ and used for the Faraday rotator. It was confirmed that it was a possible Bi-substituted rare earth iron garnet single crystal.

（実施例９）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは１９．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．０ｍｏｌ％、４９．５ｍｏｌ％、２３．１ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９５０℃まで炉温を上げてルツボ４内の材料を融解温度９５０℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。７８０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度７８０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１≒ｙ＜ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_１．５０Ｇｄ_０．８７Ｙｂ_０．６３Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄＹｂ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 Example 9
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O _{3 that} weighs 2.3 kg in total. Charged with NaOH. The compounding ratio x of Fe, Ga and Al was 19.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 8.0 mol%, 49.5 mol%, and 23.1 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 950 ° C., and the material in the crucible 4 was melted at a melting temperature of 950 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 780 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 780 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1≈y <y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. When the composition of the single crystal was analyzed by X-ray fluorescence analysis, the composition was Bi _1.50 Gd _0.87 Yb _0.63 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na could be detected. However, the composition could not be determined. Next, when the composition was evaluated in detail by ICP analysis, it was found that the chemical formula of the magnetic garnet single crystal was (BiGdYb) _2.998 Na _0.002 (FeGaAl) _5.000 O ₁₂ and used for the Faraday rotator. It was confirmed that it was a possible Bi-substituted rare earth iron garnet single crystal.

（実施例１０）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは２２．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ７．７ｍｏｌ％、４７．６ｍｏｌ％、２２．２ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９５０℃まで炉温を上げてルツボ４内の材料を融解温度９５０℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。９００℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度９００℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１＜ｙ＜ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_１．５０Ｇｄ_０．８７Ｙｂ_０．６３Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄＹｂ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 (Example 10)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O _{3 that} weighs 2.3 kg in total. Charged with NaOH. The compounding ratio x of Fe, Ga, and Al was 22.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 7.7 mol%, 47.6 mol%, and 22.2 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 950 ° C., and the material in the crucible 4 was melted at a melting temperature of 950 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 900 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 900 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1 <y <y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. When the composition of the single crystal was analyzed by X-ray fluorescence analysis, the composition was Bi _1.50 Gd _0.87 Yb _0.63 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na could be detected. However, the composition could not be determined. Next, when the composition was evaluated in detail by ICP analysis, it was found that the chemical formula of the magnetic garnet single crystal was (BiGdYb) _2.998 Na _0.002 (FeGaAl) _5.000 O ₁₂ and used for the Faraday rotator. It was confirmed that it was a possible Bi-substituted rare earth iron garnet single crystal.

（実施例１１）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは２５．５ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ７．３ｍｏｌ％、４５．５ｍｏｌ％、２１．２ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９５０℃まで炉温を上げてルツボ４内の材料を融解温度９５０℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。９００℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度９００℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１≒ｙ＜ｙ２であった。その結果、欠陥のない膜厚８０μｍの単結晶膜１２が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_１．５０Ｇｄ_０．８７Ｙｂ_０．６３Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄＹｂ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かり、ファラデー回転子に使用可能なＢｉ置換希土類鉄ガーネット単結晶であることを確認した。 (Example 11)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O _{3 that} weighs 2.3 kg in total. Charged with NaOH. The blending ratio x of Fe, Ga and Al was 25.5 mol%. Moreover, the compounding ratios of B, Bi, and Na were 7.3 mol%, 45.5 mol%, and 21.2 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 950 ° C., and the material in the crucible 4 was melted at a melting temperature of 950 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 900 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 900 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1≈y <y2. As a result, a single crystal film 12 having a film thickness of 80 μm without defects could be grown. When the composition of the single crystal was analyzed by X-ray fluorescence analysis, the composition was Bi _1.50 Gd _0.87 Yb _0.63 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na could be detected. However, the composition could not be determined. Next, when the composition was evaluated in detail by ICP analysis, it was found that the chemical formula of the magnetic garnet single crystal was (BiGdYb) _2.998 Na _0.002 (FeGaAl) _5.000 O ₁₂ and used for the Faraday rotator. It was confirmed that it was a possible Bi-substituted rare earth iron garnet single crystal.

（比較例１）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは２５．５ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ７．３ｍｏｌ％、４５．５ｍｏｌ％、２１．２ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９８０℃まで炉温を上げてルツボ４内の材料の融解及び攪拌を試みたが、炉温を上げすぎたためルツボ４が変形し単結晶の育成はできなかった。 (Comparative Example 1)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O _{3 that} weighs 2.3 kg in total. Charged with NaOH. The blending ratio x of Fe, Ga and Al was 25.5 mol%. Moreover, the compounding ratios of B, Bi, and Na were 7.3 mol%, 45.5 mol%, and 21.2 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. Attempts were made to melt and stir the material in the crucible 4 by raising the furnace temperature to 980 ° C. However, because the furnace temperature was raised too much, the crucible 4 was deformed and the single crystal could not be grown.

（比較例２）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは２５．５ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ７．３ｍｏｌ％、４５．５ｍｏｌ％、２１．２ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９５０℃まで炉温を上げてルツボ４内の材料を融解温度９５０℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。８８０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度８８０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ＜ｙ１＜ｙ２であった。育成中、融液８中に多数の固形物が析出したため単結晶膜に多数の結晶欠陥が発生し、育成した単結晶をファラデー回転子に使用することは不可能であった。 (Comparative Example 2)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O _{3 that} weighs 2.3 kg in total. Charged with NaOH. The blending ratio x of Fe, Ga and Al was 25.5 mol%. Moreover, the compounding ratios of B, Bi, and Na were 7.3 mol%, 45.5 mol%, and 21.2 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 950 ° C., and the material in the crucible 4 was melted at a melting temperature of 950 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 880 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 880 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y <y1 <y2. During the growth, a large number of solids were precipitated in the melt 8, so that a large number of crystal defects occurred in the single crystal film, and it was impossible to use the grown single crystal for the Faraday rotator.

（比較例３）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは１９．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．０ｍｏｌ％、４９．３ｍｏｌ％、２３．０ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９８０℃まで炉温を上げてルツボ４内の材料を融解して攪拌を試みたが、炉温を上げすぎたためルツボ４が変形し単結晶の育成はできなかった。 (Comparative Example 3)
The crucible 4 made of Au was filled with Gd ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O ₃ , and NaOH that totaled 2.3 kg. . The compounding ratio x of Fe, Ga and Al was 19.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 8.0 mol%, 49.3 mol%, and 23.0 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. Although the furnace temperature was raised to 980 ° C. and the material in the crucible 4 was melted and stirred, the crucible 4 was deformed and the single crystal could not be grown because the furnace temperature was raised too much.

（比較例４）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは１９．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．０ｍｏｌ％、４９．５ｍｏｌ％、２３．１ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９５０℃まで炉温を上げてルツボ４内の材料を融解温度９５０℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。７５０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度７５０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ＜ｙ１＜ｙ２であった。育成中、融液８中に多数の固形物が析出したため単結晶膜に多数の結晶欠陥が発生し、育成した単結晶をファラデー回転子に使用することは不可能であった。 (Comparative Example 4)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ , Bi ₂ O _{3 that} weighs 2.3 kg in total. Charged with NaOH. The compounding ratio x of Fe, Ga and Al was 19.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 8.0 mol%, 49.5 mol%, and 23.1 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 950 ° C., and the material in the crucible 4 was melted at a melting temperature of 950 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 750 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 750 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y <y1 <y2. During the growth, a large number of solids were precipitated in the melt 8, so that a large number of crystal defects occurred in the single crystal film, and it was impossible to use the grown single crystal for the Faraday rotator.

（比較例５）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｌａ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは９．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ８．９ｍｏｌ％、５５．５ｍｏｌ％、２５．９ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９００℃まで炉温を上げてルツボ４内の材料を融解温度９００℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。７５０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度７５０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１＜ｙ２＜ｙであった。その結果、欠陥のない膜厚８０μｍの単結晶膜が育成できた。蛍光Ｘ線分析法により単結晶を組成分析したところ、組成はＢｉ_０．４０Ｇｄ_２．５４Ｌａ_０．０６Ｆｅ_４．８０Ｇａ_０．１０Ａｌ_０．１０Ｏ_１２であり、Ｎａは検出できたが組成を確定することはできなかった。次にＩＣＰ分析法で詳しく組成を評価したところ、磁性ガーネット単結晶の化学式は、（ＢｉＧｄＬａ）_{２．９９８}Ｎａ_{０．００２}（ＦｅＧａＡｌ）_{５．０００}Ｏ_１２であることが分かった。しかしながら、育成した単結晶はＢｉ量が少なく、ファラデー回転係数が小さ過ぎるためファラデー回転子には使用できないことを確認した。 (Comparative Example 5)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , La ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ totaling a weight of 2.3 kg. , Bi ₂ O ₃ , NaOH. The blending ratio x of Fe, Ga and Al was 9.0 mol%. Moreover, the compounding rates of B, Bi, and Na were 8.9 mol%, 55.5 mol%, and 25.9 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 900 ° C., and the material in the crucible 4 was melted at a melting temperature of 900 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 750 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 750 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1 <y2 <y. As a result, a single crystal film having a thickness of 80 μm without any defects was grown. Composition analysis of the single crystal by X-ray fluorescence analysis revealed that the composition was Bi _0.40 Gd _2.54 La _0.06 Fe _4.80 Ga _0.10 Al _0.10 O ₁₂ and Na could be detected. However, the composition could not be determined. Then composition was examined in detail by the ICP analysis, the chemical formula of the magnetic garnet single crystal _was found to be _{_{_{5.000 O 12 (BiGdLa) 2.998 Na}}} 0.002 (FeGaAl). However, it was confirmed that the grown single crystal has a small amount of Bi and has a Faraday rotation coefficient that is too small to be used for a Faraday rotator.

（比較例６）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｌａ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは９．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率はそれぞれ８．９ｍｏｌ％、５５．５ｍｏｌ％、２５．９ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９００℃まで炉温を上げてルツボ４内の材料を融解温度９００℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。５８０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度５８０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ＜ｙ１＜ｙ２であった。育成中、融液８中に多数の固形物が析出したため単結晶膜に多数の結晶欠陥が発生し、育成した単結晶をファラデー回転子に使用することは不可能であった。 (Comparative Example 6)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , La ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O _{3 that} weighs 2.3 kg in total. , Bi ₂ O ₃ , NaOH. The blending ratio x of Fe, Ga and Al was 9.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 8.9 mol%, 55.5 mol%, and 25.9 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 900 ° C., and the material in the crucible 4 was melted at a melting temperature of 900 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 580 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 580 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y <y1 <y2. During the growth, a large number of solids were precipitated in the melt 8, so that a large number of crystal defects occurred in the single crystal film, and it was impossible to use the grown single crystal for the Faraday rotator.

（比較例７）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｌａ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは８．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ９．０ｍｏｌ％、５６．１ｍｏｌ％、２６．２ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９００℃まで炉温を上げてルツボ４内の材料を融解温度９００℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。７２０℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度７２０℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１＜ｙ２＜ｙであった。しかし、成長速度が低いため膜厚５μｍの単結晶膜しか得られなかった。この成長速度では育成時間を延ばしてもファラデー回転子に必要な膜厚を得ることはできないため、本比較例の育成条件は、ファラデー回転子に用いるための磁性ガーネット単結晶の育成に不適であることが分かった。 (Comparative Example 7)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , La ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O _{3 that} weighs 2.3 kg in total. , Bi ₂ O ₃ , NaOH. The compounding ratio x of Fe, Ga, and Al was 8.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 9.0 mol%, 56.1 mol%, and 26.2 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 900 ° C., and the material in the crucible 4 was melted at a melting temperature of 900 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 720 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 720 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1 <y2 <y. However, since the growth rate was low, only a single crystal film having a film thickness of 5 μm was obtained. At this growth rate, even if the growth time is extended, the film thickness required for the Faraday rotator cannot be obtained. Therefore, the growth conditions of this comparative example are unsuitable for growing a magnetic garnet single crystal for use in the Faraday rotator. I understood that.

（比較例８）
Ａｕ製のルツボ４に、合計で２．３ｋｇの重量になるＧｄ_２Ｏ_３、Ｙｂ_２Ｏ_３、Ｌａ_２Ｏ_３、Ｆｅ_２Ｏ_３、Ｇａ_２Ｏ_３、Ａｌ_２Ｏ_３、Ｂ_２Ｏ_３、Ｂｉ_２Ｏ_３、ＮａＯＨを充填した。Ｆｅ、Ｇａ及びＡｌの配合率ｘは８．０ｍｏｌ％であった。また、Ｂ、Ｂｉ、Ｎａの配合率は、それぞれ９．０ｍｏｌ％、５６．１ｍｏｌ％、２６．２ｍｏｌ％であった。材料が充填されたルツボ４を電気炉に配置した。９００℃まで炉温を上げてルツボ４内の材料を融解温度９００℃で融解して攪拌し、均一な融液８を生成した。直径２インチのＣａＭｇＺｒ置換ＧＧＧ基板１０を固定冶具２に取り付けて炉内に投入した。６００℃まで融液８の温度を下げてから基板１０の片面を融液８に接触させ、育成温度６００℃でエピタキシャル成長を４時間行った。育成温度ｙとｙ１、ｙ２との関係はｙ１＜ｙ＜ｙ２であった。しかし、成長速度が低いため膜厚１０μｍの単結晶膜しか得られなかった。この成長速度では育成時間を延ばしてもファラデー回転子に必要な膜厚を得ることはできないため、本比較例の育成条件は、ファラデー回転子に用いるための磁性ガーネット単結晶の育成に不適であることが分かった。 (Comparative Example 8)
In a crucible 4 made of Au, Gd ₂ O ₃ , Yb ₂ O ₃ , La ₂ O ₃ , Fe ₂ O ₃ , Ga ₂ O ₃ , Al ₂ O ₃ , B ₂ O ₃ totaling a weight of 2.3 kg. , Bi ₂ O ₃ , NaOH. The compounding ratio x of Fe, Ga, and Al was 8.0 mol%. Moreover, the compounding ratios of B, Bi, and Na were 9.0 mol%, 56.1 mol%, and 26.2 mol%, respectively. The crucible 4 filled with the material was placed in an electric furnace. The furnace temperature was raised to 900 ° C., and the material in the crucible 4 was melted at a melting temperature of 900 ° C. and stirred to produce a uniform melt 8. A CaMgZr-substituted GGG substrate 10 having a diameter of 2 inches was attached to the fixing jig 2 and placed in the furnace. After the temperature of the melt 8 was lowered to 600 ° C., one side of the substrate 10 was brought into contact with the melt 8 and epitaxial growth was performed at a growth temperature of 600 ° C. for 4 hours. The relationship between the growth temperature y and y1 and y2 was y1 <y <y2. However, since the growth rate was low, only a single crystal film having a thickness of 10 μm was obtained. At this growth rate, even if the growth time is extended, the film thickness required for the Faraday rotator cannot be obtained. Therefore, the growth conditions of this comparative example are unsuitable for growing a magnetic garnet single crystal for use in the Faraday rotator. I understood that.

図３は、上記の実施例及び比較例の育成条件等をまとめて示している。また、図１の●印（Ｅ１〜Ｅ１１）は実施例１〜１１での配合率ｘ及び育成温度ｙをそれぞれ示し、図１の△印（Ｃ１〜Ｃ８）は比較例１〜８での配合率ｘ及び育成温度ｙをそれぞれ示している（ただし、比較例１及び３では単結晶を育成できなかったため育成温度に代えて融解温度を示している）。図１及び図３に示すように、Ｆｅ、Ｇａ及びＡｌの配合率ｘが９．０ｍｏｌ％以上２５．５ｍｏｌ％以下である場合に、ファラデー回転子に適したＢｉ置換希土類鉄ガーネット単結晶を育成できる。また、育成温度ｙが６００℃以上９００℃以下である場合に、ファラデー回転子に適したＢｉ置換希土類鉄ガーネット単結晶を育成できる。さらに、Ｆｅ、Ｇａ及びＡｌの配合率ｘ（ｍｏｌ％）と育成温度ｙ（℃）とが４３６＋１８．２ｘ≦ｙ≦５５５＋１８．２ｘの関係を満たす場合に、ファラデー回転子に適したＢｉ置換希土類鉄ガーネット単結晶を育成できる。これらの育成条件を全て満たすことによって、ファラデー回転子に適したＢｉ置換希土類鉄ガーネット単結晶をより安定に育成できるようになる。 FIG. 3 collectively shows the growth conditions and the like of the above examples and comparative examples. 1 (E1 to E11) represents the blending ratio x and the growth temperature y in Examples 1 to 11, respectively, and Δ marks (C1 to C8) in FIG. 1 represent blends in Comparative Examples 1 to 8, respectively. The rate x and the growth temperature y are shown respectively (however, in Comparative Examples 1 and 3, since the single crystal could not be grown, the melting temperature was shown instead of the growth temperature). As shown in FIGS. 1 and 3, a Bi-substituted rare earth iron garnet single crystal suitable for a Faraday rotator is grown when the mixing ratio x of Fe, Ga and Al is 9.0 mol% or more and 25.5 mol% or less. it can. In addition, when the growth temperature y is 600 ° C. or higher and 900 ° C. or lower, a Bi-substituted rare earth iron garnet single crystal suitable for a Faraday rotator can be grown. Furthermore, when the mixing ratio x (mol%) of Fe, Ga and Al and the growth temperature y (° C.) satisfy the relationship of 436 + 18.2x ≦ y ≦ 555 + 18.2x, Bi-substituted rare earth iron suitable for a Faraday rotator Can grow garnet single crystals. By satisfying all of these growth conditions, a Bi-substituted rare earth iron garnet single crystal suitable for a Faraday rotator can be grown more stably.

本発明の一実施の形態による磁性ガーネット単結晶の製造方法における配合率ｘと育成温度ｙとの関係を示すグラフである。It is a graph which shows the relationship between the compounding rate x and the growth temperature y in the manufacturing method of the magnetic garnet single crystal by one embodiment of this invention. 単結晶を育成する工程の一部を示す図である。It is a figure which shows a part of process of growing a single crystal. 実施例１乃至１１及び比較例１乃至８の育成条件等をまとめて示す表である。It is a table | surface which shows the growth conditions etc. of Example 1 thru | or 11 and Comparative Examples 1-8 collectively.

Explanation of symbols

２固定冶具
４ルツボ
８融液
１０基板
１２単結晶膜
2 Fixing jig 4 Crucible 8 Melt 10 Substrate 12 Single crystal film

Claims

In a solvent containing Na, Bi and B, at least one element containing Fe among Fe, Ga and Al is dissolved at a blending ratio x (mol%) of 9.0 mol% or more to produce a solution,
A method for producing a magnetic garnet single crystal, comprising using the solution to grow a magnetic garnet single crystal at a growth temperature y (° C.) of 900 ° C. or less that satisfies 436 + 18.2x ≦ y ≦ 555 + 18.2x.

A method for producing a magnetic garnet single crystal according to claim 1 ,
The method for producing a magnetic garnet single crystal, wherein the solution is produced in a crucible made of Au.