JPH05343227A - Garnet thin film - Google Patents

Abstract

PURPOSE:To provide a magneto-optical garnet thin film whose stress between the substrate and the thin film is relaxed and that has a high magneto-optical effect. CONSTITUTION:In a Ce-substituted-YIG thin film formed on a crystal substrate having a garnet structure, part or the whole of iron (Fe) is replaced by Al, Ga, or both Al and Ga together. Further, part of Y is replaced by one ore more elements selected from Lu, Yb, Tm, Er, Dy, Tb, Gd, and Eu. Furthermore, part of Fe is replaced by Al, Ga, or both Al and Ga, and part of Ce is replaced by one or more elements selected from Lu, Yb, Tm, Er, Dy, Tb, and Eu.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a garnet material of a magneto-optical crystal used for an optical isolator, etc., and particularly, controlling a lattice constant difference between a substrate and a thin film within ± 0.5%,
The present invention relates to a garnet thin film that realizes stress reduction between the substrate and the thin film.

[0002]

2. Description of the Related Art As a magneto-optical material used for an optical isolator or the like, various substitution systems of thin film yttrium iron garnet (YIG) formed on a garnet substrate are used. The Faraday constant of these substitution systems is several hundred degrees / cm
When used as a 45-degree rotator, a thick film of several hundred μm was produced by the liquid phase epitaxial method and used. Here, when a thick film of several hundred μm is produced by the liquid phase epitaxial method, the growth time extends for several hundred minutes, which may cause mixing of miscellaneous crystals during growth, unevenness of film growth, generation of defects, etc. Was there. Recently, a Ce-substituted YIG thin film with high concentration substitution of cerium (Ce) for yttrium sites, which could not be produced by liquid phase epitaxial method, has been realized by the sputtering method, and the Faraday constant reaches several thousand degrees / cm. Was shown. With this thin film, several tens of μm
A 45-degree rotor can be realized with this film thickness, and it is possible to suppress characteristic deterioration due to miscellaneous crystals, uneven growth of the film, defects, etc. However, there is a large difference in lattice constant between the Ce-substituted YIG film and various garnet substrates, which causes stress between the substrate and the thin film after forming the thin film, which causes warpage, cracks, and deterioration of crystallinity. FIG. 14 is a diagram showing the results of the measurement of the warpage of the sample in the prior art. From the results of the diagram, it can be seen that a warp of about 6.8 μm occurs at both ends and the central part of the substrate.

As a result, when a thick film of several μm or more is formed, in addition to cracking and peeling of the thin film, deterioration of various optical characteristics and magneto-optical characteristics of the thin film, and formation of a fine pattern using photolithography However, various adverse effects such as the pattern dripping were caused, which had an unfavorable effect in practical use. Therefore, it is important to control the lattice constant difference between the Ce-substituted YIG thin film and the substrate to reduce the stress between the substrate and the thin film in order to manufacture a high quality and practical magneto-optical device. In particular, to achieve the above purpose, the difference in lattice constant between the substrate and the thin film should be ± 0.5.
It is desirable to control within%.

[0004]

The prior art has the above-mentioned drawbacks, and it is difficult to obtain a thin film material having a high magneto-optical effect.

The object of the present invention is to solve the problems of the prior art described above, and in the production of a magneto-optical thin film using Ce-substituted YIG, the lattice constant difference between the substrate and the thin film should be within ± 0.5%. It is an object of the present invention to provide a garnet thin film having a structure that controls and reduces stress between the substrate and the thin film and has a high magneto-optical effect.

[0006]

The above object can be achieved by using a garnet thin film having the following contents. That is, (1) in a Ce-substituted YIG thin film formed on a crystal substrate having a garnet structure, part or all of iron (Fe) is replaced with aluminum (Al), gallium (Ga) or Al.
A garnet thin film characterized by matching the lattice constants of the substrate and the thin film by substituting both of Ga, (2) Formed on a crystalline substrate having a garnet structure
In the Ce-substituted YIG thin film, part of yttrium (Y) is lutetium (Lu), ytterbium (Yb), thulium (Tm), erbium (Er), dysprosium (Dy), terbium (Tb), gadolinium (Gd), europium. (3) A garnet thin film characterized by matching the lattice constants of the substrate and the thin film by substituting one or several elements selected from (Eu), (3) On a crystalline substrate having a garnet structure In the Ce-substituted YIG thin film formed on, part of Fe is Al,
Replace with Ga or both, and replace part of Ce with Lu, Y
b, Tm, Er, Dy, Tb, Gd, a garnet thin film characterized by matching the lattice constant of the thin film with the substrate by substituting one or several elements selected from Eu, Can be achieved by

[0007]

The operation of the above-mentioned constitution of the present invention is as follows.

(1 ') In the composition of the Ce-substituted YIG thin film, a material in which a part of Fe is further substituted by Al and Ga is used to control the difference in lattice constant between the substrate and the thin film within ± 0.5%. It is possible to reduce the stress between the thin film and the thin film and to suppress the characteristic deterioration of the garnet material.

In the composition of the (2 ') Ce-substituted YIG thin film, a part of Y is further added to one or several elements selected from Lu, Yb, Tm, Er, Dy, Tb, Gd, and Eu (hereinafter, By using a material replaced with (abbreviated as R) (hereinafter, abbreviated as Ce / R-substituted YIG), the difference in lattice constant between the substrate and the thin film is ± 0.5%.
Control within to reduce the stress between the substrate and the thin film, and
A Ce high-concentration substituted garnet thin film material having a high magneto-optical effect and capable of suppressing characteristic deterioration of the garnet material can be obtained.

(3 ') Chemical formula (Ce _{3-y R'y} ) (Fe _5-z R'' _z ) O _v
In the composition of the Ce-containing iron garnet thin film of (v: ~ 12),
Part of R '' is replaced by Al or Ga or both, and part of R'is replaced by Lu, Yb, Tm, Er, Dy, Tb, G.
By using a material that is further substituted with one or several of the elements d and Eu, the lattice constant difference between the substrate and the thin film is controlled within ± 0.5%, and the stress between the substrate and the thin film is controlled. It is possible to obtain a Ce high-concentration substituted garnet thin film material having a high magneto-optical effect and capable of suppressing the deterioration of the characteristics of the garnet material.

[0011]

[Example] Ce high-concentration substitution Y produced by the sputtering method
The lattice constant of the IG thin film includes, in addition to the composition ratio of each constituent element, substrate temperature during production, oxygen flow rate, high-frequency incident power density, substrate type (substrate crystal lattice constant, plane orientation, substrate surface state, etc.). ) And other factors. But Ce replacement YIG
The lattice constant a _{f of the} thin film is largely the Ce substitution amount; x (Ce _x Y _y
Fe _z O _v ; y ~ 3-x, z ~ 5, v ~ 12) can be evaluated by the following formula.

A _f ˜12.376 + 0.193x (unit A) (1) In addition, Al and Ga in which Fe sites are formed by a sputtering method
In addition to the composition ratio of each constituent element, the lattice constant of the Ce-substituted YIG thin film substituted with is also the substrate temperature during production, oxygen flow rate, high-frequency incident power density, substrate type (substrate crystal lattice constant, plane orientation, substrate (Including surface condition)). However, the decrease Δa of the lattice constant is largely due to the amount of Al and Ga substitution at the Fe site z {[Ce / Y] _u [Fe _5-z R '' _z ].
O _v ； u 〜 3} can be used to evaluate by the following formula 0.0736z ； Al substitution △ a 〜 (unit A) (2) 0.0202z ； Ga substitution Also, Ce / R substituted YIG thin film lattice prepared by sputtering method In addition to the composition ratio of each constituent element, the constant also includes the substrate temperature during production, the oxygen flow rate, the high-frequency incident power density, the type of substrate (including the lattice constant of the substrate crystal, the plane orientation, the surface state of the substrate, etc.).
It changes depending on factors such as. However, to a large extent, the decrease Δa of the lattice constant is also the amount of R substitution y {[Ce _x R _y Y
_3-xy ] Fe ₅ O _v } can be evaluated by the following equation.

0.0357y; Lu substitution 0.0257y; Yb substitution 0.0150y; Tm substitution Δa to 0.00867y; Er substitution (unit A) (3) -0.0140y; Dy substitution -0.0180y; Tb substitution -0.0280y; Gd Substitution −0.0480y ； Eu substitution A necessary for preparing thin films with various Ce substitutions on garnet substrates with lattice constants of 12.383, 12.439, 12.496 and 12.509A while matching the lattice constants of the substrates.
Fig. 1 shows the results of calculating the amounts of l and Ga substitution from equations (1) and (2).
2 to 9 show the calculation results of Eqs. (1) and (3) for the amount of R substitution necessary to form a thin film on the above substrate while matching the lattice constant of the substrate. Similarly, Figures 10 to 13 show the results of calculating the R'and R '' substitutions required to form a thin film while matching the lattice constant of the substrate from Eqs. (1), (2), and (3). Note that in FIGS. 10 to 13, Dy,
The illustration of Tb, Gd, and Eu has been omitted to simplify the drawing.

The garnet thin film of the present invention will be specifically described below with reference to examples.

[0015]

Example 1 This example is an example in the case of replacing Fe with AL.

A film was formed on a (111) 2 inch φ substrate having a lattice constant of 12.496A by a usual high frequency sputtering method using a target of Ce _1.0 Y ₂ Fe _4.5 Al _0.5 O _x . Substrate temperature 500
° C., argon flow rate 9.9Sccm, oxygen flow rate 0 sccm, sputtering pressure 4.0 Pa, the electrode plate current density 3mA / cm ² (RF incident power 320W, reflected power 75W), and a thickness of 1 [mu] m. The composition of the obtained film was Ce _0.99 Y _2.01 Fe _4.2 Al _0.5 O _y , and warpage
No cracks or peeling of the film were observed. Further, in order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer. From the separation of the peaks of the film and substrate, the difference in lattice constant was 0.035A, which was about 0.28%, and the lattice constants of the film and substrate were in agreement. The Al composition with the matching lattice constants expected from Eqs. (1) and (2) is 0.992, but in reality, due to the heat shrinkage effect between the substrate temperature and room temperature during film formation, the composition shift of the film, etc. The composition is consistent.

[0017]

Example 2 This example is an example of replacing Fe with Ga.

A film was formed on a (111) 2 inch φ substrate having a lattice constant of 12.496A by a usual high frequency sputtering method using a target of the composition Ce _1.0 Y ₂ Fe _3.17 Ga _1.83 O _x . Substrate temperature
The temperature was 500 ° C., the argon flow rate was 9.9 sccm, the oxygen flow rate was 0.02 sccm, the sputtering pressure was 4.0 Pa, the electrode plate current density was 3 mA / cm ² (RF incident power 320 W, reflection power 75 W), and the film thickness was 3 μm. The composition of the obtained film was Ce _1.00 Y _2.00 Fe _3.15 Ga _1.84 O _y ,
No warp, crack, peeling of the film or the like was observed. Also,
In order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer. From the separation of the peaks of the film and substrate, the lattice constant difference was 0.012A and 0.096A.
%, The lattice constants of the film and the substrate were the same. (1) and
The Ga composition with the matching lattice constant expected from Eq. (2) is 3.61.
However, in reality, the above compositions are the same due to the heat shrinkage effect between the substrate temperature and the room temperature during film formation, the film composition shift, and the like.

[0019]

[Embodiment 3] This embodiment is an example in the case of co-substitution of Fe with Al and Ga.

A film was formed on a (111) 2 inch φ substrate having a lattice constant of 12.496A by a usual high frequency sputtering method using a target having a composition of Ce _1.0 Y ₂ Fe _3.12 Al _0.40 Ga _1.48 O _x .
Substrate temperature 500 ℃, Argon flow rate 9.9sccm, Oxygen flow rate 0.02sc
cm, sputter pressure 4.0Pa, electrode plate current density 3mA / cm
² (RF incident power 320 W, reflection power 75 W) and film thickness 10 μm. The composition of the obtained film is Ce _1.00 Y _2.00 Fe _3.12 Al _0.48 Ga
_{It was 1.48} O _y , and no warp, crack, film peeling, or the like was observed. Further, in order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer. The lattice constant difference is 0 due to the separation of the peaks of the film and substrate.
The lattice constants of the film and the substrate were the same at about 006A and about 0.05%. The lattice constants expected from Eqs. (1) and (2) match A
The l and Ga compositions are 0.97 and 2.64, respectively, but in reality, the above compositions are the same due to the heat shrinkage effect between the substrate temperature and the room temperature during film formation, the film composition shift, and the like.

[0021]

[Embodiment 4] This embodiment is an example of substitution with Ce ₂ .

A film was formed on a (111) 2 inch φ substrate having a lattice constant of 12.496A by a usual high frequency sputtering method using a target of the composition Ce _2.0 Y _1.0 Fe _3.01 Al _1.99 O _x . The substrate temperature was 500 ° C., the argon flow rate was 9.9 sccm, the oxygen flow rate was 0 sccm, the sputtering pressure was 4.0 Pa, the electrode plate current density was 3 mA / cm ² (RF incident power 320 W, reflection power 75 W), and the film thickness was 1 μm. The composition of the obtained film is Ce _1.99 Y _1.01 Fe _2.99 Al _1.98 O _y ,
No warp, crack, peeling of the film or the like was observed. Also,
In order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer. From the separation of the peaks of the film and the substrate, the lattice constant difference was 0.042A, which was about 0.34%, and the lattice constants of the film and substrate were the same. The Al composition for which the lattice constants expected from Eqs. (1) and (2) match is 3.61, but in reality, due to the heat shrinkage effect between the substrate temperature and room temperature during film formation, the compositional shift of the film, etc. The composition is consistent.

[0023]

[Embodiment 5] This embodiment is an example of replacement of Y with Lu.

A film was formed on a (111) 2 inch φ substrate having a lattice constant of 12.496A by a conventional high frequency sputtering method using a target having a composition of Ce _1.0 Lu _1.04 Y _0.96 Fe _5.0 O _x . Substrate temperature 500 ℃, Argon flow rate 9.9sccm, Oxygen flow rate 0.04sccm, Sputtering pressure 4.0Pa, Electrode plate current density 3mA / cm ² (RF
The incident power was 320 W, the reflection power was 75 W, and the film thickness was 1 μm.
The composition of the obtained film was Ce _0.99 Lu _1.04 Y _0.97 Fe _4.8 O _y , and no warp, crack, peeling of the film, or the like was observed. Further, in order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer.
From the separation of the peaks of the film and substrate, the lattice constant difference was 0.036 A and 0.29.
%, The lattice constants of the film and the substrate were the same. (1) and
The Lu composition with lattice constants expected from Eq. (2) is 2.04.
Although it is 5, the above compositions are actually the same because of the heat shrinkage effect between the substrate temperature and the room temperature during film formation, the compositional shift of the film, and the like.

When the Faraday rotation angle of the sample of this example was measured, a high magneto-optical effect of 3000 deg / cm was obtained.

[0026]

Sixth Embodiment This embodiment is an example in the case of replacing Y by Yb.

A film was formed on a (111) 2 inch φ substrate having a lattice constant of 12.496A by a usual high frequency sputtering method using a target of the composition Ce _1.0 Yb _1.44 Y _0.56 Fe ₅ O _x . Substrate temperature
The temperature was 500 ° C., the argon flow rate was 9.9 sccm, the oxygen flow rate was 0.02 sccm, the sputtering pressure was 4.0 Pa, the electrode plate current density was 3 mA / cm ² (RF incident power 320 W, reflection power 75 W), and the film thickness was 3 μm. The composition of the obtained film was Ce _1.00 Yb _1.43 Y _0.57 Fe _4.8 O _y ,
No warp, crack, peeling of the film or the like was observed. Also,
In order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer. The lattice constant difference is 0.011A and 0.088% from the separation of the peaks of the film and substrate.
The lattice constants of the film and the substrate were almost the same. (1) and (2)
The Yb composition for which the lattice constant is expected from the equation is 2.84, but in reality it is the same for the above composition due to the thermal contraction effect between the substrate temperature and room temperature during film formation, the film composition shift, and other factors.

When the Faraday rotation angle of the sample of this example was measured, a high magneto-optical effect of 2000 deg / cm was obtained.

[0029]

[Embodiment 7] This embodiment is an example in the case of co-substitution of Y with Yb and Lu.

A film was formed on a (111) 2 inch φ substrate having a lattice constant of 12.496A by a usual high frequency sputtering method using a target of the composition Ce _1.0 Lu _0.52 Yb _0.72 Y _0.76 Fe _5.0 O _x .
Substrate temperature 500 ℃, Argon flow rate 9.9sccm, Oxygen flow rate 0.02sc
cm, sputter pressure 4.0Pa, electrode plate current density 3mA / cm
² (RF incident power 320 W, reflection power 75 W) and film thickness 10 μm. The composition of the obtained film is Ce _1.00 Lu _0.51 Yb _0.71 Y _0.78 Fe
_{It was 4.8} O _y , and no warp, crack, peeling of the film, or the like was observed. Further, in order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer. The lattice constant difference is 0 due to the separation of the peaks of the film and substrate.
The lattice constants of the film and the substrate were the same at about 006A and about 0.05%. L that matches the lattice constant expected from Eqs. (1) and (2)
The u and Yb compositions are 1.023 and 1.42, but in reality, the above compositions are the same due to the heat shrinkage effect between the substrate temperature and the room temperature during film formation, the compositional shift of the film, and the like.

[0031]

[Embodiment 8] This embodiment is an example of replacement with Ce _0.5 .

A film was formed on a (111) 2 inch φ substrate having a lattice constant of 12.496A by a usual high frequency sputtering method using a target of the composition Ce _0.50 Tb _0.66 Y _1.84 Fe _5.0 O _x . Substrate temperature 500 ℃, Argon flow rate 9.9sccm, Oxygen flow rate 0sccm, Sputtering pressure 4.0Pa, Electrode plate current density 3mA / cm ² (RF
The incident power was 320 W, the reflection power was 75 W, and the film thickness was 1 μm.
The composition of the obtained film was Ce _0.49 Tb _0.65 Y _1.86 Fe _4.8 O _y , and warpage, cracks, peeling of the film, and the like were not observed. Further, in order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer.
From the separation of the peaks of the film and substrate, the lattice constant difference is 0.042A and 0.34A.
%, The lattice constants of the film and the substrate were the same. (1) and
The Tb composition in which the lattice constant expected from Eq. (2) matches is 1.31.
However, in reality, the above compositions are the same because of the heat shrinkage effect between the substrate temperature and the room temperature during film formation, the film composition shift, and the like.

[0033]

[Embodiment 9] This embodiment is an example of the replacement of Y with Yb.

[0034] The film was formed by the lattice constants 12.496A (111) 2 inches φ composition on a substrate Ce _2.00 Yb _1.00 Fe conventional RF sputtering method using a target of _3.51 Al _{1. 49} O _x. Substrate temperature 500 ℃, Argon flow rate 9.9sccm, Oxygen flow rate 0.02scc
m, sputter pressure 4.0Pa, electrode plate current density 3mA / cm ²
(RF incident power 320 W, reflection power 75 W) and film thickness 3 μm. The composition of the obtained film is Ce _1.99 Yb _1.01 Fe _3.32 Al _1.48 O _y
No warpage, cracks, film peeling, etc. were observed. Further, in order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer. The lattice constant difference is 0.012A from the separation of the peaks of the film and substrate.
At about 0.096%, the lattice constants of the film and substrate matched.
The lattice constants expected from Eqs. (1), (2), and (3) match.
The Al composition is 3.26, but in reality, the above compositions are in agreement due to the heat shrinkage effect between the substrate temperature and the room temperature during film formation, the compositional deviation of the film, and the like.

When the Faraday rotation angle of the sample of this example was measured, a high magneto-optical effect of 4000 deg / cm was obtained.

[0036]

[Embodiment 10] This embodiment is an example of replacement of Ce with Lu.

[0037] The film was formed by the lattice constants 12.496A (111) 2 inches φ composition on a substrate Ce _1.50 Lu _1.50 Fe _3.38 Ga _1. using a target of ₆₂ O _x normal frequency sputtering. Substrate temperature 500 ℃, Argon flow rate 9.9sccm, Oxygen flow rate 0.04scc
m, sputter pressure 4.0Pa, electrode plate current density 3mA / cm ²
(RF incident power 320 W, reflection power 75 W) and film thickness 1 μm. The composition of the obtained film is Ce _1.50 Lu _1.50 Fe _3.18 Ga _1.60 O _y
No warpage, cracks, film peeling, etc. were observed. Further, in order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer. The lattice constant difference is 0.032A from the separation of the peaks of the film and substrate.
At about 0.26%, the lattice constants of the film and substrate matched.
The lattice constants expected from Eqs. (1), (2), and (3) match.
Although the Ga composition is 5.74, the above composition is actually the same due to the heat shrinkage effect between the substrate temperature and the room temperature during film formation, the film composition shift, and the like.

When the Faraday rotation angle of the sample of this example was measured, a high magneto-optical effect of 3700 deg / cm was obtained.

[0039]

Example 11 This example shows Al substitution of Fe and Y substitution of Ce.
This is an example of the case of b and Lu co-substitution.

[0040] The film was formed by composition of a lattice constant 12.496A (111) 2 inches φ substrate Ce _1.50 Lu _0.75 Yb _0.75 Fe _4. using a target of ₄₅ Al _0.55 O _x normal frequency sputtering. Substrate temperature 500 ° C, Argon flow rate 9.9sccm, Oxygen flow rate 0.
02sccm, sputter pressure 4.0Pa, electrode plate current density 3m
A / cm ² (RF incident power 320W, reflected power 75W), film thickness 10μ
It was m. The composition of the obtained film was Ce _1.49 Lu _0.76 Yb _0.75 Fe.
_{Since it was 4.40} Al _0.54 O _y , no warp, crack, peeling of the film or the like was observed. Further, in order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer. From the separation of the peaks of the film and substrate, the difference in lattice constant was 0.006A, which was about 0.05%, and the lattice constants of the film and substrate were in agreement. The Al composition where the lattice constants expected from Eqs. (1), (2), and (3) match is 1.68. As a result, the above compositions are the same.

[0041]

[Embodiment 12] This embodiment is an example in the case of Al substitution of Fe and substitution of Ce _2.5 .

[0042] The film was formed by the lattice constants 12.496A (111) 2 inches φ composition on a substrate Ce _2.50 Lu _0.50 Fe _2.74 Al _2. using a target of ₂₆ O _x normal frequency sputtering. Substrate temperature 500 ℃, Argon flow rate 9.9Sccm, Oxygen flow rate 0sccm,
Sputtering pressure 4.0Pa, Electrode plate current density 3mA / cm ² (R.
F. Incident power 320 W, reflection power 75 W), and film thickness 1 μm. The composition of the obtained film is Ce _2.49 Lu _0.51 Fe _2.51 Al _2.27 O _y
No warpage, cracks, film peeling, etc. were observed. Further, in order to obtain the lattice constant of the film, the (444) diffraction peak profile of the film and the substrate was examined by a double crystal X-ray diffractometer. The lattice constant difference is 0.042A from the separation of the peaks of the film and substrate.
And the lattice constants of the film and the substrate were about 0.34%.
The lattice constants expected from Eqs. (1), (2), and (3) match.
Although the Al composition is 4.68, the above composition is actually the same due to the heat shrinkage effect between the substrate temperature and the room temperature during film formation, the film composition shift, and the like.

[0043]

As described above, in the production of the magneto-optical thin film using Ce-substituted YIG, the problem of the prior art was solved by using the thin film of the present invention as the structure of the thin film. , The lattice constant difference between the substrate and the thin film is ± 0.5%
It was possible to provide a garnet thin film having a structure in which the stress between the substrate and the thin film was controlled within a range and which had a high magneto-optical effect.

[Brief description of drawings]

[Fig.1] Calculation of Al and Ga substitution amounts required to form thin films with various Ce substitution amounts on the garnet substrate with lattice constants of 12.383, 12.439, 12.496 and 12.509 while matching the substrate lattice constant. The figure which shows the result.

[Fig. 2] Necessary for producing thin films having various Ce substitution amounts on the above substrate while matching the substrate lattice constant.
The figure which shows the result of having calculated the amount of Lu substitution.

[Fig. 3] Necessary for producing thin films having various Ce substitution amounts on the above substrate while matching the substrate lattice constant.
The figure which shows the result of having calculated the Yb substitution amount.

FIG. 4 Necessary for producing thin films having various Ce substitution amounts on the above substrate while matching the substrate lattice constant.
The figure which shows the result of having calculated Tm substitution amount.

FIG. 5: Necessary for producing thin films having various Ce substitution amounts on the above substrate while matching the substrate lattice constant.
The figure which shows the result of having calculated the Er substitution amount.

FIG. 6 is necessary for producing thin films having various Ce substitution amounts on the above substrate while matching the substrate lattice constant.
The figure which shows the result of having calculated the Dy substitution amount.

FIG. 7: Necessary for producing thin films having various Ce substitution amounts on the above substrate while matching the substrate lattice constant.
The figure which shows the result of having calculated the Tb substitution amount.

FIG. 8: Necessary for producing thin films with various Ce substitution amounts on the above substrate while matching the substrate lattice constant
The figure which shows the result of having calculated Gd substitution amount.

FIG. 9: Necessary to prepare thin films having various Ce substitution amounts on the above substrate while matching the substrate lattice constant.
The figure which shows the result of having calculated the substitution amount of Eu.

FIG. 10: Substrate lattice constants of Al, Ga and Lu, Yb, Tm, Er, Y substitutions necessary for producing thin films having various Ce contents on a garnet substrate while matching the substrate lattice constants. The figure which shows the result calculated about 12.383A.

FIG. 11: Substrate lattice constants of Al, Ga and Lu, Yb, Tm, Er, Y substitutions necessary for producing thin films having various Ce contents on a garnet substrate while matching with the substrate lattice constants. The figure which shows the result calculated about 12.439A.

FIG. 12: Substrate lattice constants of Al, Ga and Lu, Yb, Tm, Er, Y substitutions necessary for producing thin films having various Ce contents on a garnet substrate while matching the substrate lattice constants. The figure which shows the result calculated about 12.496A.

FIG. 13: Substrate lattice constants of Al, Ga and Lu, Yb, Tm, Er, Y substitutions necessary for producing thin films having various Ce contents on a garnet substrate while matching the substrate lattice constants. The figure which shows the result calculated about 12.509A.

FIG. 14 is a diagram showing a result when warpage was measured for a sample after a thin film was formed in the conventional technique.

Claims (3)

[Claims] 1. A cerium-substituted yttrium iron garnet thin film formed on a crystal substrate having a garnet structure, wherein a part or all of iron is replaced by aluminum, gallium, or both aluminum and gallium to obtain a lattice constant between the substrate and the thin film. A garnet thin film characterized by matching. 2. In a cerium-substituted yttrium iron garnet thin film formed on a crystal substrate having a garnet structure, a part of yttrium is selected from the group consisting of lutetium, ytterbium, thulium, erbium, dysprosium, terbium, gadolinium and europium. A garnet thin film characterized in that the lattice constants of the substrate and the thin film are matched by substituting with several kinds of elements. 3. A cerium-iron garnet thin film formed on a crystal substrate having a garnet structure, wherein iron is partially replaced by aluminum, gallium or both, and
Characterized by substituting part of cerium with one or several elements selected from lutetium, ytterbium, thulium, erbium, dysprosium, terbium, gadolinium, and europium to match the lattice constants of the substrate and the thin film. Garnet thin film.