Tdk Corporation

Atsushi Ohido

Kazuhito Yamasawa

Tamotsu Sugawara

Katsumi Kawasaki

Shinichiro Kakei

Kazuya Shimakawa

Katsunori Hosoya

Kenichi Tohchi

A substratecomprises: a first layer Lcontaining crystalline aluminum nitride; a second layer Lcontaining crystalline &#x3b1;-alumina; and an intermediate layer Lm sandwiched between the first layer Land the second layer Land containing aluminum, nitrogen, and oxygen, and the content of nitrogen in the intermediate layer Lm decreases in a direction Z from the first layer Ltoward the second layer L, and the content of oxygen in the intermediate layer Lm increases in the direction Z from the first layer Ltoward the second layer L

Substrate and light-emitting element

An alumina substrate on which an AlN layer is formed and that causes less warping, and a substrate material strong enough to withstand normal handling when an AlN crystal is grown upon it, and prevents cracking and fracturing of a grown crystal when stress is applied during growing or cooling. The substrate has a gap and a rare earth element-containing region inside the AlN layer or at the interface between the AlN layer and the alumina substrate. Warping of the AlN layer can be reduced by lattice-mismatch stress being concentrated at the region and releasing of stress by the gap. The region having a concentrating of stress, and the gap having a low mechanical strength, can induce crackings and fracturings. As a result, contamination of crackings and fracturings into the crystal grown on the substrate can be prevented. The region can ensure a level of mechanical strength sufficient for handling.

Alumina substrate

An alumina substrate having a carbon-containing phase with an AlN layer formed on a surface of the alumina substrate.

An alumina substrate wherein an AlN layer is formed on a surface of the alumina substrate and a rare earth elements-containing layer and/or rare earth elements-containing regions is/are formed in the interior of the AlN layer or in the interface between the AlN layer and the alumina substrate.

The present invention relates to a magnetic garnet single crystal prepared by the liquid phase epitaxial (LPE) process and an optical element using the same as well as a method of producing the single crystal, for the purpose of providing a magnetic garnet single crystal at a reduced Pb content and an optical element using the same, as well as a method of producing the single crystal. The magnetic garnet single crystal is grown by the liquid phase epitaxial process and is represented by the chemical formula BiNaPbM1FeM2O(M1 is at least one element selected from Y, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; and M2 is at least one element selected from Ga, Al, In, Ti, Ge, Si and Pt, provided that 0.5&#x3c;x&#x2266;2.0, 0&#x3c;y&#x2266;0.8, 0&#x2266;z&#x3c;0.01, 0.19&#x2266;3-x-y-z&#x3c;2.5, and 0&#x2266;w&#x2266;1.6).

Magnetic garnet single crystal and optical element using same as well as method of producing single crystal

The invention relates to a magnetic garnet single crystal and an optical element using the same, for the purpose of providing a magnetic garnet single crystal at a reduced Pb content, and an optical element using the same, where the magnetic garnet single crystal is represented by the chemical formula BiM1FeM2M3O(M1 is at least one element selected from Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; and M2 is Si; and M3 is at least one element selected from Zn, Ni, Cu and Mg, provided that 0.5&#x3c;&#x3b1;&#x2266;2.0, 0&#x3c;&#x3b2;, and 0&#x3c;y).

Magnetic garnet single crystal and optical element using the same

The invention relates to a method of producing an optical element using a garnet single crystal for the purpose of providing an optical element with a reduced Pb content or from which Pb can preliminarily be removed completely. By growing a garnet single crystal by using a solution containing Na, Bi and B by the LPE process and thermally treating the garnet single crystal in reducing atmosphere prepared by using nitrogen gas and/or hydrogen gas, the resulting thermally treated garnet single crystal is used to prepare an optical element.

Method of producing optical element

The present invention relates to a magnetic garnet single crystal prepared by the liquid phase epitaxial (LPE) process and an optical element using the same as well as a method of producing the single crystal, for the purpose of providing a magnetic garnet single crystal at a reduced Pb content and an optical element using the same, as well as a method of producing the single crystal. The magnetic garnet single crystal is grown by the liquid phase epitaxial process and is represented by the chemical formula BiNaPbM1FeM2O(M1 is at least one element selected from Y, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; and M2 is at least one element selected from Ga, Al, In, Ti, Ge, Si and Pt, provided that 0.5&#x3c;x&#x2266;2.0, 0&#x3c;y&#x2266;0.8, 0&#x2266;z&#x3c;0.01, 0.19&#x2266;3&#x2212;x&#x2212;y&#x2212;z&#x3c;2.5, and 0&#x2266;w&#x2266;1.6).

It is an object of the present invention to provide a magnetic garnet single crystal capable of reducing the optical loss of the resulting rotator even when the magnetic garnet single crystal is grown using a solvent containing Na by the liquid phase epitaxial process, as well as a Faraday rotator using the same. A magnetic garnet single crystal represented by the chemical formula BiNaM1M2FeMgM3O(M1 is at least one element or more selected from Y, Eu, Gd, Tb, Dy, Ho, Yb and Lu; and M2 is at least one element or more selected from Ca and Sr; M3 is at least one element or more selected from Si, Ge, Ti, Pt, Ru, Sn, Hf and Zr, provided that 0.60&#x3c;&#x3b1;&#x2266;1.50, 0&#x3c;&#x3b2;&#x2266;0.05, 1.35&#x3c;3&#x2212;&#x3b1;&#x2212;&#x3b2;&#x2212;&#x3b3;&#x3c;2.40, 0&#x2266;&#x3b3;&#x2266;0.10, 0&#x2266;&#x3b4;&#x2266;0.10, 0&#x3c;&#x3b5;&#x2266;0.10, 0&#x3c;&#x3b3;+&#x3b4;&#x2266;0.10, 0&#x3c;&#x3b4;+&#x3b5;&#x2266;0.10).

Magnetic garnet single crystal and Faraday rotator using the same

It is an object of the present invention to provide a magnetic garnet single crystal at a reduced Pb content, and a method for producing the same and an optical element using the same. The object is attained with a magnetic garnet single crystal represented by the chemical formula BiNaM1FeM2O(M1 is at least one element selected from Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; and M2 is at least one element selected from Si, Ge and Ti, provided that 0.5&#x3c;&#x3b1;&#x2266;2.0, 0&#x3c;&#x3b2;&#x2266;0.8, 0.2&#x2266;3&#x2212;&#x3b1;&#x2212;&#x3b2;&#x3c;2.5, and 0&#x3c;&#x3b3;&#x2266;1.6).

Magnetic garnet single crystal and method for producing the same as well as optical element using the same

Proposed is a technique of producing a magnetic garnet material of which the light absorption characteristics worsen little even though it is produced through LPE. The crucible for LPE is formed of a material containing Au. The amount of Au to be taken in single crystal formed in an Au crucible is smaller than that of Pt to be taken therein formed in a Pt crucible. As compared with Pt, the influence of Au on magnetic garnet film that increases the insertion loss in the film is small.

Magnetic garnet material, faraday rotator, optical device, bismuth-substituted rare earth-iron-garnet single-crystal film and method for producing the same and crucible for producing the same

A of producing a magnetic garnet material of which the light absorption characteristics worsen little even though it is produced through LPE. The crucible for LPE is formed of a material containing Au. The amount of Au to be taken in single crystal formed in an Au crucible is smaller than that of Pt to be taken therein formed in a Pt crucible. As compared with Pt, the influence of Au on magnetic garnet film that increases the insertion loss in the film is small.

Magnetic garnet material, faraday rotator, optical device, bismuth-substituted rare earth-iron-garnet single-crystal film and method for producing the same crucible for producing the same

A hard magnetic Bi-substituted rare earth iron garnet material with excellent Faraday rotary moment, temperature property, wavelength property and insertion loss is provided. A Bi-substituted rare earth iron garnet material having a chemical composition of (BiGdTbYb) FeMO(where, M is at least one element selected from the group consisting of Ga, Al, Ge, Sc, In, Si and Ti, 0.5&#x2266;a+b+c&#x2266;2.5, 0.2&#x2266;w&#x2266;2.5) can be provided with hard magnetism and have excellent Faraday rotary moment, temperature property, wavelength property and insertion loss.

Hard magnetic garnet material, faraday rotator, optical device, optical communication system, method of manufacturing faraday rotator and method of manufacturing bismuth-substituted rare earth iron garnet single crystal

There are provided a manufacturing method of an optical device excellent in expediency, and a technique for stably manufacturing a high performance optical device. After a single crystal film which constitutes a Faraday rotator and can exhibit a substantially rectangular magnetic hysteresis, is obtained, the single crystal film is magnetized in a state where this single crystal film is incorporated in an optical device such as an optical isolator. By performing a magnetizing step after the Faraday rotator is incorporated in the optical device, it becomes unnecessary to discriminate between the front and back surfaces of the single crystal film, and the characteristics of the optical device are also improved.

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Tokyo, Japan

Atsushi Ohido