Sony Corporation

Tsutomu Okamoto

Koichi Tatsuki

Shigeo Kubota

Yoshikazu Murakami

Hitoshi Tamada

Masahiko Kaneko

Kanako Niikura

Koji Watanabe

Yoshimi Makino

Hidemasa Tamura

Koichi Aso

Hiroyuki Nakano

Kazutaka Habu

Toshiro Yamada

Takahiro Ohgihara

Tatsuo Fukui

Yasuyuki Mizunuma

Yasushi Minoya

Takahiro Ogihara

Yasujiro Taguchi

Disclosed is a method for the growth of a single crystal having excellent crystallinity, uniform quality in the inside thereof and hence excellently uniform optical properties, the method enabling an improvement in yields. The invention resides in a method for the growth of a single crystal of &bgr;-type barium borate (&bgr;-BaB,O,), the method comprising heating a crucible,indirectly to grow a &bgr;-BaB,O,single crystal,from a melt of barium borate (BaB,O,) contained in the crucible and using no flux by using a seed crystal,of &bgr;-BaB,O,.

Method for single crystal growth and growth apparatus

In a single-crystal manufacturing method, after a single crystal is grown, the crystal is separated from the molten melt and gradually cooled while suspended immediately above the surface of the melt. During this cooling, a measure, which produces solidification of the melt, is locally applied. As a result, the solidification of the melt is selectively forced so that at least the melt forms a crust and prevents the crystal, should it fall, from becoming immersed in molten melt. This measure also protects the crystal from any sudden release of heat such as tends to occur if the melt becomes supercooled prior to the onset of crystallization.

Single crystal manufacturing method

A method of growing a single crystal of KTiOPO.sub.4 which is a nonlinear optical material is disclosed. Growth of the single crystal of KTiOPO.sub.4 is carried out by melting a KTiOPO.sub.4 material with a flux to produce a melt, then contacting a seed crystal to the melt, and by slowly cooling at a saturation temperature or below. At this time, molar fractions of K.sub.2 O, P.sub.2 O.sub.5 and TiO.sub.2 contained in the melt fall within a region surrounded by six point in a K.sub.2 O-P.sub.2 O.sub.5 -TiO.sub.2 ternary phase diagram of A (K.sub.2 O:0.4150, P.sub.2 O.sub.5 :0.3906, TiO.sub.2 : 0.1944), B (K.sub.2 O:0.3750, P.sub.2 O.sub.5 : 0.3565, TiO.sub.2 : 0.2685), C (K.sub.2 O: 0.3750, P.sub.2 O.sub.5 : 0.3438, TiO.sub.2 : 0.2813), D (K.sub.2 O: 0.3850, P.sub.2 O.sub.5 : 0.3260, TiO.sub.2 : 0.2890), E (K.sub.2 O: 0.4000, P.sub.2 O.sub.5 : 0.3344, TiO.sub.2 : 0.2656), and F (K.sub.2 O: 0.4158, P.sub.2 O.sub.5 : 0.3744, TiO.sub.2 : 0.2098). In addition, K.sub.15 P.sub.13 O.sub.40 or the same composition produced by melting is used as the flux, and the proportion of a KTiOPO.sub.4 element in a composition of the melt is prescribed to 83.5 to 90.0 mol %. The seed crystal is set so that a C axis is in a direction perpendicular to a melt surface. Then, the seed crystal contacted to the melt is rotated and slowly cooled. Thus, a single crystal of KTiOPO.sub.4 of single domain at the end of growth can be produced.

Method of producing single crystal of KTiOPO.sub.4

A method is provided for producing a KTiOPO.sub.4 which is grown at a temperature higher than its Curie temperature using a TSSG method. The grown KTiOPO.sub.4 single crystal is maintained in contact with a melt while the crystal is maintained at a temperature higher than the Curie temperature. A d.c. current is applied in this state across a seed crystal and the melt, while the single crystal is cooled to a temperature lower than the Curie temperature. The value of current density D, defined by the formula D=Ip/(a+b), where Ip is the impressed current and a, b are crystal sizes along a and b axes, respectively, is selected to be 0.01 mA/cm.sup.2 .ltoreq.D.ltoreq.1.0 mA/cm.sup.2. In this manner, the produced KTiOPO.sub.4 is processed into a single domain crystal.

Method for producing KTIOPO4 single crystal

A ferromagnetic resonance device is disclosed which utilize the perpendicular resonance of ferrimagnetic YIG thin film operable under a D.C. bias magnetic field perpendicular to a major surface of the YIG thin film element. By making the YIG thin film to have a major surface thereof (100) crystal plane of YIG or (111) crystal plane of a substituted YIG having reduced Ku value, lower limit of resonance frequency is extremely lowered. Thus wide range variable filter device can be obtained.

Ferromagnetic resonance device

An optical waveguide device is disclosed which utilizes an interaction between a guided optical wave and a magnetostatic wave. The optical waveguide device comprises a layer of bismuth substituted magnetic garnet which guides an optical wave. A pair of electrodes coupled to the layer of the magnetic garnet generates a magnetostatic backward volume wave in the layer of the magnetic garnet under an application of a certain bias magnetic field. The guided optical wave and the magnetostatic wave interact with each other wherein adverse effect caused by a spin effect is avoided to realize high efficiency at high frequency.

Optical waveguide device

A tuned oscillator utilizing a thin film ferromagnetic resonator is disclosed. The oscillator comprises an active element for oscillator and a YIG thin film resonator connected to the active element as a part of feed-back circuit for the active element. The YIG thin film resonator is applied with a bias magnetic field perpendicular to a surfce of a YIG disk which is generated by a permanent magnet for a fixed component and a coil for a variable component for the resonance frequency. The resonance frequency is stabilized by use of a PLL circuit connected to an output of the oscillator and feeding back to the coil. Since the YIG thin film tuned oscillator has a high Q value, high quality communication signal processing can be achieved. The YIG tuned oscillator is used as local oscillator for a transciever.

Tuned oscillator utilizing thin film ferromagnetic resonator

Thermomagnetic recording system

A thin (less than 500.mu.m) epitaxial dielectric layer having low photoconductivity is grown on a monocrystalline wafer composed of Bi.sub.12 GeO.sub.20 by a liquid-phase epitaxial growth technique. The composition of the liquid melt from which the dielectric layer is grown is composed of a pseudo-three-component system defined by the formula:

Method of producing a dielectric of two-layer construction

An alloy for a magnetoresistive element has an ordered phase with superstructure and consists of nickel and cobalt atoms, and the ratio of the nickel atoms to the cobalt atoms by the number of atoms is substantially within the range of 40:60 to 60:40. A method of manufacturing an alloy for a magnetoresistive element includes the steps of preparing a substrate for a magnetoresistive element, and forming so a nickel-cobalt alloy film on the substrate at the temperature of more than 250.degree. C. that the alloy has an ordered phase with superstructure and the ratio of the nickel atoms to the cobalt atoms by the number of atoms is within the range of 40:60 to 60:40.

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Kanagawa, Japan

Tsutomu Okamoto