JPH1050521A - Magneto-optical film and manufacturing method thereof - Google Patents

Abstract

(57) [Problem] To provide a magneto-optical film having a small loss and a large Faraday effect. A _{Gd 3 (Sc t Ga 5-} t) O 12 (t ≦
On a substrate having the composition _{2), Ce X Y 3-} x Fe 5 + y O
A magneto-optical film characterized by forming a magneto-optical film substantially having a composition of _{12 + z} (x ≦ 3, −0.5 ≦ y, z ≦ 0.5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magneto-optical material used for optical communication, optical measurement, optical control, memory, etc.
The present invention relates to a magneto-optical film having a small loss and a large Faraday effect, and a method for manufacturing the same.

[0002]

2. Description of the Related Art An optical non-reciprocal circuit such as an optical isolator or an optical circulator uses Faraday rotation of light, which is a kind of magneto-optical effect. Conventionally, as a magneto-optical material, YIG (Y ₃ Fe ₅ O ₁₂ ) or a part of Y
Bi-substituted YIG crystals replaced by Y have been used.
To reduce the size and increase the performance of the circuit, a magneto-optical material having a large Faraday rotation angle and a small propagation loss is required. Recently, there has been an increasing demand for a waveguide made of a magneto-optical material film for the purpose of integrating an optical circuit. In particular, it is important that the magneto-optical material used in the optical integrated circuit has a low propagation loss as well as a large Faraday rotation angle.

As a material having a large Faraday rotation angle, a magneto-optical film of Ce-substituted YIG (Ce _X Y _3-x Fe ₅ O ₁₂ ) in which part of Y is replaced by Ce is currently being developed. As a substrate, a GGG (Gd ₃ Ga ₅ O ₁₂ ) substrate having a lattice constant smaller than that of the film (a lattice constant of 12.38)
3Å), SGGG ([Gd, Ca, Mg] ₃ [Ga, Z
r] ₃ O ₁₂ ) substrate (lattice constant 12.495 °), NGG
(Nd ₃ Ga ₅ O ₁₂ ) substrate (lattice constant 12.509 °)
Was used. (Literature: Uno, Shintaku, "Ce: YI
Substrate Dependence of G Thin Film Magneto-Optical Properties ", Proceedings of the 39th Joint Lecture Meeting on Applied Physics, 28a-H-8, P51 (1
However, although the conventional Ce-substituted YIG film has a large Faraday rotation angle, the propagation loss is 13-18 dB / c.
m and a high defect. Therefore, reduction of propagation loss has been desired.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed to improve the above-mentioned disadvantages, and an object of the present invention is to provide a magneto-optical film having a small loss and a large Faraday effect.

[0005]

To achieve the above object, according to an aspect of the present invention on a substrate having a composition of _{Gd 3 (Sc t Ga 5-} t) O 12 (t ≦ 2), Ce X Y 3-x Fe _{5 + y} O
A magneto-optical film characterized by forming a magneto-optical film substantially having a composition of _{12 + z} (x ≦ 3, −0.5 ≦ y, z ≦ 0.5) is a feature of the present invention. The present invention is different from the prior art in the material composition.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates, Gd ₃ (Sc _t Ga
_5-t ) Ce _X on a substrate having a composition of O ₁₂ (t ≦ 2)
Y _3-x Fe _{5 + y} O _{12 + z} (x ≦ 3, −0.5 ≦ y, z ≦
0.5) forming a magneto-optical film having the composition described above.

[0007]

Next, an embodiment of the present invention will be described. The embodiment is merely an example, and it goes without saying that various changes or improvements can be made without departing from the spirit of the present invention. In this embodiment, the crystal substrate having a composition of _{Gd 3 (Sc t Ga 5-} t) O 12 (t ≦ 2) by high-frequency _{sputtering, Ce X Y 3-x Fe} 5 + y O
A Ce-substituted YIG magneto-optical crystal film having a composition of _{12 + z} (x ≦ 3, −0.5 ≦ y, z ≦ 0.5) was formed. For the target, powders of CeO ₂ , Y ₂ O ₃ , and Fe ₂ O ₃ were mixed to have a desired composition and sintered. At this time, although the amount of oxygen increases, oxygen can be released at the time of sputtering, so that it can be adjusted at that time. As a sputtering gas, an argon gas containing a small amount of oxygen was used in order to prevent oxygen escape (a pure argon gas can also be used). The substrate temperature was 500 ° C. or higher. After sputtering, the film is formed at 750 to 850 ° C. in nitrogen (inert gas or vacuum) at 30 to 9
A 0 minute annealing was performed.

[0008] The chemical composition Gd ₃ of the crystalline substrate (Sc _t G
a _5-t ) O ₁₂ (t ≦ 2), t does not exceed 2 crystallographically, and the chemical composition Ce of the Ce-substituted YIG film is Ce
_X Y _3-x Fe _{5 + y} O _{12 + z} (x ≦ 3, −0.5 ≦ y, z ≦
In 0.5), x does not exceed 3 because the substitution amount for yttrium C _e. Further, crystallographically, iron element (Fe) is 5 and oxygen element (O) is 12, that is, y =
0, z = 0 is desirable, but y of the manufactured film is
And z may have an error of about ± 0.5.

Next, the Ce-substituted YI prepared according to the present invention is used.
The characteristics of the G magneto-optical film will be described. FIG. 1 shows Gd ₂ Sc
Crystal substrate having a composition of ₂ Ga ₃ O ₁₂ (a =＝ 12.56
5}) is an example of the propagation characteristics of a crystal film having a composition of CeY ₂ Fe ₅ O ₁₂ on the (111) plane at an optical wavelength of 1.55 μm. Light was guided in the direction of the film surface by the prism coupling method, and the amount of light attenuation with respect to the propagation distance was measured. From the slope of the straight line, the propagation loss is 9.7 dB / cm in TEmode and T
5.8dB / cm in Mmode
(B / cm). The Faraday rotation angle also showed a large value of about 3200 deg / cm.

[0010]

As described above, the present invention provides a Gd
_{3 (Sc t Ga 5-t} ) to O ₁₂ on a substrate having a (t ≦ 2) _{composition, Ce X Y 3-x Fe} 5 + y O 12 + z (x ≦ 3, -0.
Forming a magneto-optical film having a composition of (5 ≦ y, z ≦ 0.5) has an effect of obtaining a magneto-optical film having low loss and a large Faraday effect.

[Brief description of the drawings]

FIG. 1 shows a diagram of propagation loss characteristics of an embodiment that best illustrates the features of the present invention.

Claims (2)

[Claims] 1. A _{Gd 3 (Sc t Ga 5-} t) O 12 (t ≦
On a substrate having the composition _{2), Ce X Y 3-} x Fe 5 + y O
A magneto-optical film characterized by forming a magneto-optical film substantially having a composition of _{12 + z} (x ≦ 3, −0.5 ≦ y, z ≦ 0.5). 2. The method according to claim 1, wherein the film is formed by sputtering.