JPH07234427A - Production of nonlinear optical material - Google Patents

Abstract

PURPOSE:To form a waveguide by depositing a thin film of a single crystal of KNbO3, LiNbO3, a solid soln. of them, etc., on a substrate without restriction on the faces of the substrate. CONSTITUTION:A thin film of a single crystal represented by the general formula XYO3 (where X is at least one kind of element selected from among potassium, sodium, lithium and silver and Y is at least one kind of element selected from among niobium, tantalum and antimony) is deposited and grown on a substrate to product the objective nonlinear optical material. At this time, the substrate has a lattice constant close to that of the single crystal represented by the general formula and does not cause phase transition under conditions of the deposition and growth of the thin film of the single crystal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a non-linear optical material in which a single crystal thin film is deposited and grown on a substrate. According to the present invention, it is possible to provide a non-linear optical material using a single crystal thin film having a potassium niobate crystal structure excellent in wavelength conversion ability in the 800 nm region. An optical waveguide type wavelength conversion element can be provided by using the non-linear optical material of the present invention. This element is a wavelength conversion element capable of highly efficient conversion, and in recent years, optical disc recording has been highly demanded from various fields. It can be sufficiently used as a light source for applications, various visible light sensors, physicochemical measurement, and the like.

[0002]

2. Description of the Related Art In recent years, coherent light of a shorter wavelength in the green to blue to ultraviolet region has been required due to the demand for higher density recording on optical recording media and various visible light sensors. One way to get this kind of light is
There is a method of halving the fundamental wavelength of the laser by using the second-order nonlinear optical effect. In utilizing this effect, in many cases, inorganic and organic crystals having a second-order nonlinear optical effect are used.

Currently used inorganic non-linear optical crystals include, for example, KNbO ₃ , LiNbO ₃ and KTi.
Examples include OPO ₄ , β-BaB ₂ O ₄ , and Ba ₂ NaNb ₅ O ₁₅ . Among these crystals, KNbO ₃ (KN) has a large second-order nonlinear optical effect and is important as a crystal capable of direct wavelength conversion of a semiconductor laser on the order of 800 nm (Appl.Phys.Lett.35 ( 6), 15 September 1979,461〜
463). Furthermore, KNbO ₃ is also excellent in mechanical strength.
In addition, LiNbO ₃ (LN) has a large nonlinear optical constant and is relatively easy to grow (J. Cry. Grout).
h. 99 (1990) 832-836).

[0004]

Further, in order to obtain light in the visible and ultraviolet regions with high efficiency, research and devising of a device structure in which the inorganic non-linear optical crystal as described above is made into a fiber or a waveguide is performed at the same time. Is in progress.

For example, a LiNbO ₃ single crystal thin film is formed into LiT.
There is known a method of forming a thin film waveguide by matching the lattice constants of the a-axes of each single crystal when forming it on an aO ₃ substrate [JP-A-3-218997]. However, LiNbO ₃ by itself is not suitable for wavelength conversion of a semiconductor laser on the order of 800 nm, and it is necessary to add a device such as doping LiNbO ₃ with another element. However, if an attempt is made to deposit LiNbO ₃ doped with another element on the substrate, the crystal structure of LiNbO ₃ doped with another element will change subtly, so that a single crystal thin film cannot be grown with good reproducibility. there were.

On the other hand, KNbO ₃ , NaNbO ₃ , and further, single crystals of solid solutions thereof, unlike LiNbO ₃ , can perform wavelength conversion of a semiconductor laser on the order of 800 nm without doping with other elements. However, so far, a non-linear optical material in which these KNbO ₃ -based single crystal thin films are formed on a substrate is not known. Further, generally, when a single crystal thin film is deposited on a substrate, the crystal plane of the substrate is limited by the crystal structure of the single crystal that forms the thin film. For example, in the case of the waveguide described in JP-A-3-218997, the desired plane is the (0001) plane of the LiTaO ₃ substrate. However, the required physical properties differ depending on the application of the waveguide, and thus the optimum surface of the single crystal thin film may differ depending on the application. However, until now, a single crystal thin film could be formed only on a specific surface of a specific substrate, and a new substrate had to be selected to form a single crystal thin film on another surface. .

Therefore, the object of the present invention is to limit the single crystal thin film of KNbO ₃ , LiNbO ₃ and solid solutions thereof, which have a large nonlinear optical constant and a small laser damage and can be used at room temperature, to the surface of the substrate. The object is to provide a method for forming a waveguide by depositing the waveguide without any treatment.

[0008]

The present invention is directed to the general formula XYO.
₃ [wherein X is at least one element selected from the group consisting of potassium, sodium, lithium and silver (provided that when lithium is contained as X, the content of lithium is 20 mol% or less, 80 mol% or more is at least one element selected from the group consisting of potassium, sodium and silver), Y is at least one element selected from the group consisting of niobium, tantalum and antimony (provided that Y is Y In the case of containing antimony, the content of antimony is 10 mol% or less, and the remaining 90 mol% or more is at least one element selected from the group consisting of niobium and tantalum)]. A method for manufacturing a non-linear optical material in which precipitation growth is performed on the substrate, wherein the substrate has a lattice constant close to that of the single crystal represented by the general formula. A, and the precipitated growing conditions of the single crystal thin film, to the manufacturing method, which is a phase transition does not cause a single crystal.

The single crystal used as the thin film in the present invention is represented by the general formula XYO ₃ . X is at least one element selected from the group consisting of potassium, sodium, lithium and silver. X may be a solid solution containing two or more of these elements, provided that when X contains lithium, the content of lithium is 20 mol% or less. This is because when the lithium content exceeds 20 mol%, the crystal structure changes and the function as a wavelength conversion element is impaired.

Y is at least one element selected from the group consisting of niobium, tantalum and antimony. Y may be a solid solution containing two or more of these elements, but when antimony is included as Y, the content of antimony is 10 mol% or less. Antimony is 10 mol%
This is because if it exceeds, it becomes difficult to form a solid solution.

1 and 2, (Na _1-x K _x ) NbO ₃
The change (measured value) of the lattice constant when the amount ratio of potassium to sodium is changed is shown. FIG. 1 shows changes in the lattice constants of the a-axis and the b-axis, and FIG. 2 shows changes in the lattice constant of the c-axis. In this way, the lattice constant can be adjusted by changing the amount ratio of potassium and sodium according to the physical properties required for the single crystal to be a thin film.
The same can be done when X is other than a combination of potassium and sodium. Regarding Y, the lattice constant of the single crystal thin film can be adjusted by appropriately combining two or more kinds of elements. In the present invention, the lattice constant was determined from the peak that matches the Bragg diffraction condition from the result obtained by the powder X-ray method.

On the other hand, according to the manufacturing method of the present invention, the substrate has a lattice constant close to that of the single crystal to be the thin film, and does not cause a phase transition under the precipitation growth condition of the single crystal thin film. Use crystals. The closeness of the lattice constant of the single crystal that forms the thin film and the lattice constant of the substrate means that the lattice mismatch between the lattice constant of the substrate and the single crystal that forms the thin film is within 11%, preferably It means within 5%, more preferably within 3%. Here, the lattice mismatch means a value obtained by dividing a value obtained by dividing an absolute value of a difference in lattice constant by a lattice constant of the substrate for each axis of abc of each single crystal forming a thin film on the substrate by a percentage display. However, depending on the combination of the substrate and the thin film, not only one cycle of the lattice constant but also the absolute value of the difference between two or more cycles may be used.

Further, in the present invention, a single crystal that does not cause a phase transition under the conditions of precipitation growth of a single crystal thin film is used as a substrate. The conditions for depositing and growing the single crystal thin film differ depending on the composition of the single crystal thin film and the composition of the solution or melt used for depositing the thin film. In particular, when a flux is used in the solution used for thin film deposition, the deposition temperature can be significantly reduced. Generally, the deposition temperature is in the range of 550 to 1500 ° C, preferably 900 to 1200 ° C. Therefore, in the present invention, a single crystal that does not cause a phase transition in the range of room temperature to 1500 ° C. is used as the substrate.

The single crystal which can be used as a substrate and the lattice constant (reference value) thereof satisfying the above conditions are exemplified below. ─────────────────────────────────── Single crystal lattice constant: a axis b axis c axis (Å) ─ ────────────────────────────────── SmAlO ₃ 5.285 5.290 7.473 EuAlO ₃ 5.271 _{5.292 7.458 GdAlO 3 5.247 5.304 7.417 YAlO} 3 5.179 5.329 7.370 NdGaO 3 5.431 5.499 7.710 PrGaO 3 5.465 5.495 7.729 LaCrO ₃ 5.477 5.514 7.755 PrCrO ₃ 5.444 5.484 7.710 NdCrO ₃ 5.412 5.494 7.695 SmCrO ₃ 5.372 5.502 7.650 EuCrO ₃ 5.330 5 .500 7.610 GaC rO ₃ 5.312 5.514 7.611 DyCrO ₃ 5.260 5.510 7.500 YCrO ₃ 5.247 5.518 7.540 ErCrO ₃ 5.220 5.510 7.510 YbCrO ₃ 5.180 5 .490 7.510 LuCrO ₃ 5.170 5.490 7.460 LaFeO ₃ 5.545 5.562 7.851 PrFeO ₃ 5.495 5.578 7.810 NdFeO ₃ 5.441 5.573 7.753 SmFe. ₃ 5.394 5.592 7.711 EuFeO ₃ 5.371 5.611 7.686 GdFeO ₃ 5.346 5.616 7.668 YFeO ₃ 5.279 5.590 7.609 ErFeO ₃ 5.2260 5. _{590 7.580 YbFeO 3 5.220 5.580 7.560 LuFeO} 3 5. _{10 5.550 7.550 LaScO 3 5.678 5.787 8.098} PrScO 3 5.615 5.776 8.027 NdScO 3 5.574 5.771 7.998 SmScO 3 5.530 5.760 7. 950 EuScO ₃ 5.510 5.760 7.940 GdScO ₃ 5.487 5.756 7.925 DyScO ₃ 5.430 5.710 7.890 LaInO ₃ 5.723 5914 8.207 NdInO ₃ 5.891 8.121 SmInO ₃ 5.589 5.886 8.082 ───────────────────────────────── ──

In the present invention, since a single crystal in which the lattice mismatch between the thin film and the substrate is within 11% on any of the abc axes is used, no matter which surface of the substrate is used,
A single crystal thin film can be produced with good reproducibility. For example, the lattice mismatch between the NdGaO ₃ substrate and the KNbO ₃ single crystal thin film is shown below. ─────────────────────────────────── Lattice constant: a axis b axis c axis (Å) ─── ──────────────────────────────── NdGaO ₃ substrate 5.431 5.499 7.710 KNbO ₃ single crystal thin film * 5.689 5.7256 3.9692 (7.9384) Lattice mismatch (%) 4.75 4.12 2.96 (2 cycles) ─────────────────────────────────── * Actual measurement value

[0016] Similarly, NdGaO ₃ substrate and NaNbO ₃
The lattice mismatch with the single crystal thin film is shown below. ─────────────────────────────────── Lattice constant: a axis b axis c axis (Å) ─── ──────────────────────────────── NdGaO ₃ substrate 5.431 5.499 7.710 NaNbO ₃ single crystal thin film * 5.523 5.575 3.833 (7.666) Lattice mismatch (%) 1.69 1.38 0.57 (2 cycles) ─────────────────────────────────── * Actual measurement value

As a method for producing the thin film, a liquid phase epitaxial method can be used. The liquid phase epitaxial method is
The desired surface of the single crystal to be the substrate is cut out, the single crystal substrate surface obtained by polishing is immersed in a melt having the same composition as the single crystal thin film or a solution for depositing a single crystal of the desired composition, and the substrate This can be performed by forming a desired single crystal thin film on the surface. For example, KNbO ₃ on an NdGaO ₃ substrate
When forming a single crystal thin film, use NdGaO ₃ substrate with KNb.
It can be formed by immersing in a solution for depositing O ₃ and epitaxially growing a KNbO ₃ single crystal thin film on the substrate. Melt composition, temperature, immersion time, etc.
It can be appropriately determined in consideration of the composition and thickness of the single crystal thin film. Incidentally, after forming the thin film, a single domain treatment may be performed if desired.

The non-linear optical material of the present invention produced as described above can constitute an optical waveguide type optical element or the like. The thin film single crystal of the present invention can be used as many optical waveguide type optical elements (for example, non-linear optics and electro-optical elements) according to its physical properties. In particular, the single crystal of the present invention is
Since it has a large second-order nonlinearity, it can be used as an optical element for wavelength conversion.

[0019]

EXAMPLES The present invention will be described in more detail below with reference to examples. Various thin film single crystals were produced using NdGaO ₃ , LaInO ₃ or YAlO ₃ as the substrate. Melt composition at the time of manufacturing, the nudged the single crystal of KNbO _{3 based,} KNbO 3 -KVO ₃ system phase diagram (P.Bohac, P.Bu
chamnn and H. Melchior, Japanese Journal of Applied
Physics., Vol.24 (1985), 24-2, 613-615) KNb
O ₃ : KVO ₃ = 1: 1 or KNbO ₃ : KVO ₃ =
With reference to 1: 4, KNbO ₃ is precipitated and the desired crystal composition is (Ag _1-x K _x ) NbO ₃ or (Ag _1-x K).
_x ) (Nb _1-y Sb _y ) O ₃ or the composition was changed or AgNO ₃ or Sb ₂ O ₅ was added. The manufacturing equipment is a crucible furnace (heating element Kanthal wire,
Maximum use temperature: 1200 ° C.) was used. Made of platinum as a crucible 75 mmφ × 25 mm h. × 0.2 mmt. About 180 g of each composition was used. When the composition temperature is 1: 1, the manufacturing temperature is around 950 to 1000 ° C., 1:
In the case of No. 4, the temperature was around 850 to 900 ° C., and the temperature was adjusted to about 50 ° C. depending on the difference in the degree of supercooling. The four corners of the substrate were horizontally fixed to a jig made of platinum, immersed in the melt while being rotated, and various conditions were changed to form a film. The production conditions were a rotation speed of 50 to 100 rpm and a production time of 10 to 60 minutes, and the production time was adjusted according to the desired film thickness. Immediately after the production, the substrate was rotated on the crucible surface at high speed (500 to 1000).
(rpm) was performed for 30 to 60 seconds to remove the adhered solvent. The temperature drop after production is 50 ° C / hour (production temperature ~ 60
0 ° C.), 5 ° C./hour (600 ° C. to room temperature).

Example 2-1 The substrate has a plane orientation of (100) and a size of 11.
NdGaO ₃ of 0 × 9.5 × 0.5 mm was used. KN
Using the melt of bO ₃ : KVO ₃ = 1: 4, a KNbO ₃ single crystal thin film was formed on the NdGaO ₃ substrate under the conditions shown above. As a result, a KN having a film thickness of sufficient quality as an optical waveguide for optical use is in the range of about 0.5 to 10.0 μm.
A bO ₃ thin film single crystal was formed by changing the deposition time to prepare an optical material of the present invention. After polishing both end faces of the obtained optical material, the light of 870 nm of Ti: Al ₂ O ₃ laser was incident from the end face of the single crystal thin film which is the waveguide layer. As a result, as shown in FIG. It was confirmed that the light of 870 nm and the light of second high frequency 435 nm were emitted from the wave and the end face. The propagation loss at that time is about 1.0 dB / c
It was m. In addition, NdGaO ₃ and KNbO ₃ are a
4.75% of lattice misalignment of axis, b-axis and c-axis, 4.
12% and 2.96 (2 cycles)%. The substrate is NdGaO ₃
A thin film single crystal was similarly prepared with the (110) plane or the (010) plane. KNbO ₃ with different directions
An optical material having a single crystal thin film could be obtained.

Example 2-2 A substrate having a plane orientation of (110) and a size of 10.
NdGaO ₃ of 0 × 9.0 × 0.5 mm was used. As a preparation solution, Na ₂ O: Nb ₂ O ₅ = 33: 67 to 69:
A melt in the range of 31 was used. The temperature was set according to the composition by changing the degree of supercooling in the range of about 1000 to 1430 ° C. Particularly in this example, Na ₂ O: Nb ₂ O ₅ =
When using a two-point melt of 65:35 and 45:55 and the temperature is 65:35, 1150 to 1200 ° C, 45: 5
In the case of 5, the temperature was set in the range of 1350 to 1400 ° C and the degree of supercooling was changed. Other conditions were almost the same as the above conditions, and a NaNbO ₃ single crystal thin film was formed on the NdGaO ₃ substrate. As a result, a NaNbO ₃ thin film single crystal having a film thickness of sufficient quality as an optical waveguide for optical use in a range of about 0.5 to 10.0 μm is formed by changing the deposition time to obtain the optical material of the present invention. It was made. Incidentally, Nd
GaO ₃ and NaNbO ₃ have lattice mismatches of 1.69%, 1.38%, and 0.57 (2 cycles)% on the a-axis, the b-axis, and the c-axis, respectively. A thin film single crystal was similarly prepared by using the substrate as a (100) face or a (010) face of NdGaO ₃ . An optical material having a NaNbO ₃ single crystal thin film having different directions could be obtained.

Example 2-3 The procedure of Example 1 was repeated except that Ag was added to the melt so that crystals having x of 0.5 were precipitated (Ag
_{A 1-x} K _x ) NbO ₃ (x = 0.5) single crystal thin film was prepared on NdGaO ₃ having a plane orientation of (100). As a result, (Ag _1-x K _x ) Nb having a film thickness of sufficient quality as an optical waveguide for optical use is in the range of about 0.5 to 10.0 μm.
An O ₃ thin film single crystal was formed by changing the deposition time to prepare an optical material of the present invention. Substrate is NdGaO
_{When a} single crystal thin film was similarly prepared with the (110) plane or the (010) plane of ₃ (Ag),
_1-x K _x) NbO ₃ optical material having a single-crystal thin film was obtained. In addition, NdGaO ₃ and (Ag _1-x K _x ) NbO
₃ (x = 0.5) means that the lattice mismatches of the a-axis, the b-axis, and the c-axis are 3.77%, 3.24%, and 2.20 (2 cycles)%, respectively. When the Ag element is dissolved in KNbO ₃ as in this example, the lattice constant becomes smaller from the ionic radius of Ag, and N
Since the lattice constant is close to that of dGaO ₃ , matching is facilitated and a higher quality thin film single crystal can be obtained.

Example 2-4 Ag so that crystals with x of 0.3 are precipitated in the melt.
In the same manner as in Example 1 except that Sb was added so that y was 0.05 (Ag _1-x K _x ).
The _{(Nb 1-y Sb y)} O 3 single crystal thin film, the plane orientation of (10
0) was prepared on NdGaO ₃ . As a result, a film of sufficient quality as an optical waveguide for optical use is about 0.5 to
(Ag _1-x K _x ) (Nb _1-y Sb in the range of 10.0 μm
_y ) O ₃ thin film single crystals were formed by changing the deposition time to produce the optical material of the present invention. Substrate is NdG
When a single crystal thin film was similarly prepared using the (110) plane or the (010) plane of aO _3, a (Ag _1-x K _x ) (Nb _1-y Sb _y ) O ₃ single crystal thin film having different orientations was obtained. An optical material having was obtained. In addition, NdGaO ₃ and (Ag
_{1-x K x) (Nb} 1-y Sb y) NbO 3 (x = 0.3,
y = 0.05) means that the lattice mismatches of the a-axis, the b-axis and the c-axis are 4.14%, 3.58% and 2.49 (2 cycles)%, respectively. When the Ag element and the Sb element are simultaneously dissolved in KNbO ₃ as in this example, the lattice constant becomes small from the ionic radius thereof and becomes close to the lattice constant of NdGaO ₃ .
Matching becomes easier, and a higher quality thin film single crystal can be obtained.

Example 2-5 Sb was prepared so that crystals having y of 0.05 were precipitated in the melt.
In the same manner as in Example 1 except that
The _{(Nb 1-y Sb y)} O 3 single crystal thin film, the plane orientation of (10
Preparation was performed on NdGaO _{3 of} 0). As a result, a film thickness of sufficient quality as an optical waveguide for optical use is about 0.5 to 1
A K (Nb _1-y Sb _y ) O ₃ thin film single crystal in the range of 0.0 μm was formed by changing the deposition time to produce the optical material of the present invention. The substrate is made of NdGaO ₃ (11
When thin film single crystals were similarly prepared with the (0) plane or the (010) plane, K (Nb _{1 -y} Sb) with different orientations was obtained.
_y ) An optical material having an O ₃ single crystal thin film was obtained. still,
NdGaO ₃ and _{K (Nb 1-y Sb y} ) NbO 3 (y =
0.05) means that the lattice mismatch of a-axis, b-axis and c-axis is
They are 4.73%, 4.10% and 2.95 (2 cycles)%, respectively.
When the Sb element is simultaneously dissolved in KNbO ₃ as in this example, the lattice constant decreases from the ionic radius,
Since it is close to the lattice constant of GaO ₃ , matching can be easily achieved, and a higher quality thin film single crystal can be obtained.

Example 2-6 A substrate having a plane orientation of (110) and a size of 10.
LaInO ₃ of 0 × 15.0 × 0.5 mm was used. K
Using the melt of NbO ₃ : KVO ₃ = 1: 4, a KNbO ₃ single crystal thin film was formed on the LaInO ₃ substrate under the conditions described above. As a result, a film having a sufficient quality as an optical waveguide for optical use has a K value in the range of about 0.5 to 10.0 μm.
NbO ₃ thin film single crystals were formed by changing the deposition time to produce the optical material of the present invention. In addition, LaIn
O ₃ and KNbO ₃ have lattice mismatches of 0.06%, 3.19%, and 3.27% on the a-axis, the b-axis, and the c-axis, respectively. A single crystal thin film was similarly prepared by using the substrate as LaInO ₃ (100) plane or (010) plane. An optical material having KNbO ₃ single crystal thin films having different orientations could be obtained.

Example 2-7 A substrate having a plane orientation of (110) and a size of 10.
YAlO ₃ of 0 × 15.0 × 0.5 mm was used. KN
Using the melt of bO ₃ : KVO ₃ = 1: 4, a KNbO ₃ single crystal thin film was formed on the YAlO ₃ substrate under the above conditions. As a result, a KNb having a film thickness of sufficient quality as an optical waveguide for optical use is in the range of about 0.5 to 10.0 μm.
An O ₃ thin film single crystal was formed by changing the deposition time to prepare an optical material of the present invention. In addition, YAlO ₃ and KNbO ₃ have a lattice mismatch of a-axis, b-axis and c-axis,
10.6%, 6.77% and 7.71% respectively. YA board
A single crystal thin film was similarly prepared with the (100) plane or the (010) plane of 10 ₃ . KN with different directions
An optical material having a bO ₃ single crystal thin film could be obtained.

[0027]

According to the manufacturing method of the present invention, a single crystal thin film such as KNbO ₃ , LiNbO ₃ or a solid solution thereof having a large nonlinear optical constant and a small laser damage and usable at room temperature is formed on a substrate surface. Without limitation, it is possible to provide a method for forming a waveguide by deposition.
The nonlinear optical material obtained by the manufacturing method of the present invention is useful as an optical waveguide type optical element, for example, a nonlinear optical element.

[Brief description of drawings]

FIG. 1 shows changes in lattice constants (measured values) on the a-axis and the b-axis when the amount ratio of potassium and sodium in (Na _1-x K _x ) NbO ₃ was changed.

FIG. 2 shows changes in the lattice constant (actually measured value) of the c-axis when the amount ratio of potassium and sodium in (Na _1-x K _x ) NbO ₃ was changed.

FIG. 3 shows generation of light of 435 nm, which is a second harmonic, when the single crystal thin film of Example 1 was irradiated with light of Ti: Al ₂ O ₃ laser of 870 nm.

Claims (4)

[Claims] 1. The general formula XYO ₃ [wherein X is potassium,
It is at least one element selected from the group consisting of sodium, lithium and silver (provided that when X is lithium, the content of lithium is 20 mol% or less,
The remaining 80 mol% or more is at least one element selected from the group consisting of potassium, sodium and silver),
Y is at least one element selected from the group consisting of niobium, tantalum and antimony (provided that when Y is antimony, the content of antimony is 10 mol%).
And the remaining 90 mol% or more is at least one element selected from the group consisting of niobium and tantalum)] in the method for producing a non-linear optical material in which a single crystal thin film is deposited and grown on a substrate. The substrate is a single crystal that has a lattice constant close to that of the single crystal represented by the general formula and that does not cause a phase transition under the conditions of precipitation and growth of the single crystal thin film. Said manufacturing method. 2. The lattice mismatch between the lattice constant of the substrate and the lattice constant of the single crystal constituting the thin film is within 11%.
The manufacturing method described. 3. The substrate is SmAlO ₃ , EuAlO ₃ ,
GdAlO ₃ , YAlO ₃ , NdGaO ₃ , PrGaO
₃ , LaCrO ₃ , PrCrO ₃ , NdCrO ₃ , Sm
CrO ₃ , EuCrO ₃ , GaCrO ₃ , DyCr
O ₃ , YCrO ₃ , ErCrO ₃ , YbCrO ₃ , Lu
CrO ₃ , LaFeO ₃ , PrFeO ₃ , NdFeO
₃ , SmFeO ₃ , EuFeO ₃ , GdFeO ₃ , YF
eO ₃ , ErFeO ₃ , YbFeO ₃ , LuFeO ₃ ,
LaScO ₃ , PrScO ₃ , NdScO ₃ , SmSc
O ₃ , EuScO ₃ , GdScO ₃ , DyScO ₃ , L
The manufacturing method according to claim 1 or 2, which is a thin single crystal selected from the group consisting of aInO ₃ , NdInO _3, and SmInO ₃ . 4. The manufacturing method according to claim _{3, wherein the} substrate is an NdGaO ₃ single crystal.