Abstract: A ceramic main body 1 is composed of a (Mn,Ni)3O4- or (Mn,Co)3O4-based ceramic material. A first phase has a spinel structure. A second phase is formed of high-resistance plate crystals. The second phase is present in the first phase in a dispersed state. A heated pathway having a predetermined pattern is formed on a surface of the ceramic main body by the application of heat by laser irradiation. In the heated pathway, the second phase disappears and is crystallographically equivalent to the first phase. The plate crystals of the second phase precipitate at 800° C. or lower in the cooling substep during firing. The formation of the heated pathway facilitates the adjustment of the resistance of an NTC thermistor. Thereby, provided are an NTC thermistor ceramic with a resistance that can be easily adjusted to a lower value even after sintering, a method for producing the NTC thermistor ceramic, and an NTC thermistor.

Abstract: An optical material includes lithium tantalate, and a molar composition ratio of lithium oxide and tantalum oxide (Li2O/Ta2O5) in the lithium tantalate is in the range of 0.975 to 0.982. Since an optical material having a high refractive index is provided in an optical unit, at the same focal distance, a lens thickness can be significantly reduced. As a result, an optical electronic component and an optical electronic device including the optical material has a reduced size and thickness and is highly functional.

Abstract: A ceramic main body 1 is composed of a (Mn,Ni)3O4— or (Mn, Co)3O4-based ceramic material. A first phase has a spinel structure. A second phase is formed of high-resistance plate crystals. The second phase is present in the first phase in a dispersed state. A heated pathway having a predetermined pattern is formed on a surface of the ceramic main body by the application of heat by laser irradiation. In the heated pathway, the second phase disappears and is crystallographically equivalent to the first phase. The plate crystals of the second phase precipitate at 800° C. or lower in the cooling substep during firing. The formation of the heated pathway facilitates the adjustment of the resistance of an NTC thermistor. Thereby, provided are an NTC thermistor ceramic with a resistance that can be easily adjusted to a lower value even after sintering, a method for producing the NTC thermistor ceramic, and an NTC thermistor.

Abstract: A TE-TM mode converter is provided which is capable of performing a TE-TM conversion in a wide bandwidth. In a TE-TM mode converter using an electrooptic effect, a waveguide is formed on a substrate using lithium tantalate having a birefringence of about 0.0005 or less. The direction of an optical axis of lithium tantalate forming the waveguide is approximately parallel to a primary surface of the substrate. In addition, a first electrode and a second electrode are provided on the primary surface of the substrate so as to face each other with the waveguide placed therebetween.

Abstract: An optical material includes lithium tantalate, and a molar composition ratio of lithium oxide and tantalum oxide (Li2O/Ta2O5) in the lithium tantalate is in the range of 0.975 to 0.982. Since an optical material having a high refractive index is provided in an optical unit, at the same focal distance, a lens thickness can be significantly reduced. As a result, an optical electronic component and an optical electronic device including the optical material has a reduced size and thickness and is highly functional.

Abstract: A TE-TM mode converter is provided which is capable of performing a TE-TM conversion in a wide bandwidth. In a TE-TM mode converter using an electrooptic effect, a waveguide is formed on a substrate using lithium tantalate having a birefringence of about 0.0005 or less. The direction of an optical axis of lithium tantalate forming the waveguide is approximately parallel to a primary surface of the substrate. In addition, a first electrode and a second electrode are provided on the primary surface of the substrate so as to face each other with the waveguide placed therebetween.

Abstract: A method for manufacturing a langasite single crystal substrate comprises the steps of polishing at least one of the main surfaces of a raw material substrate; and wet-etching said polished main surface of the substrate with a solution including H3PO4, HNO3 and CH3COOH.

Abstract: A surface acoustic wave resonator includes a piezoelectric substrate made of a langasite single crystal and an interdigital transducer made of Al provided on the surface of the piezoelectric substrate. A Euler angle (&phgr;, &thgr;, &phgr;) of the piezoelectric substrate is approximately (0°, 140° to 150°, 24° ±1°), and the film thickness H of the interdigital transducer is within the range of about 0.005 to 0.15 with respect to the wavelength &lgr; of a surface acoustic wave generated on the piezoelectric substrate.

Abstract: A method for manufacturing a langasite single crystal substrate comprises the steps of polishing at least one of the main surfaces of a raw material substrate; and wet-etching said polished main surface of the substrate with a solution including H3PO4, HNO3 and CH3COOH.

Abstract: A surface acoustic wave device includes a piezoelectric substrate made of a Langasite single crystal and at least one interdigital transducer including a pair of comb-shaped electrodes which are interdigitated with each other and are in contact with the piezoelectric substrate. The piezoelectric substrate has a Euler angle of approximately (0.degree., 130.degree. to 170.degree., 23.degree. to 30.degree.), whereby the surface acoustic wave device has an excellent TCD and also has a large K.sup.2 value.

Abstract: The magnetostatic wave device comprises a single crystal substrate made of Gd.sub.3 Ga.sub.5 O.sub.12, a magnetic garnet single crystal film provided on the single crystal substrate and at least one transducer provided on the magnetic garnet single crystal film. The magnetic garnet single crystal film has {111} plane and is made of a material expressed by the formula (YR.sub.1).sub.3 (FeR.sub.2).sub.5 O.sub.12, where R.sub.1 is at least one element selected from La, Bi, Lu and Gd, R.sub.2 is at least one element selected from Ga, Al, In and Sc and Y and Fe are the main components with respect to R.sub.1 and R.sub.2. In the magnetostatic wave device, a DC magnetic field is applied to the magnetic garnet single crystal film so that a magnetostatic surface wave propagates on the magnetic garnet single crystal film in a direction of <110> axis on {111} plane of the magnetic garnet single crystal film.

Abstract: Provided is an oxide single crystal of large size having the crystal structure of Ca.sub.3 Ga.sub.2 Ge.sub.4 O.sub.14 and containing Ge as a constituent element and a method of manufacturing thereof. The oxide single crystal is obtained by a manufacturing method comprising the steps of preparing a melt of starting materials containing GeO.sub.2 and growing said oxide crystal from said melt of starting materials in single-crystal growing atmosphere, which is characterized in that said starting materials contain GeO.sub.2 in a stoichiometrically excess amount, and/or said single-crystal growing atmosphere is a gas having an oxygen partial pressure greater than about 2.times.10.sup.-1 atm.

Abstract: A ferromagnetic resonance measuring cavity resonator comprises a cavity resonator having a cavity formed by a side wall. The side wall is provided with an input/output hole and a through-hole. A ferromagnetic plate provided with a through-hole is mounted on the outside surface of the side wall such that the two through-holes are aligned. A wafer specimen is pressed against the ferromagnetic plate to face the through-hole. When microwaves are introduced into the cavity resonator, ferromagnetic resonance takes place based on the static magnetic field applied to the wafer specimen and the microwaves. As a result, a ferromagnetic resonance signal is detected via the input/output hole.

Abstract: Disclosed herein is a magnetostatic wave device that employs a single-crystal thin film of the formula Y.sub.3-x M.sub.x Fe.sub.5-y N.sub.Y O.sub.12 (where M denotes at least one member selected from La, Bi, Lu, and Gd, N denotes at least one member selected from Al, In, and Sc, and x and y are defined as 0<x.ltoreq.1.0 and 0<y.ltoreq.1.5, respectively) which is formed by liquid phase epitaxy on a single-crystal substrate of Gd.sub.3 Ga.sub.5 O.sub.12, characterized in that said single-crystal thin film has a lattice constant larger than that of said single-crystal substrate, with the difference (.increment.a) between the two lattice constants being in the range defined by 0.0004 nm.ltoreq..increment.a.ltoreq.0.001 nm. It has good characteristic properties (e.g., low insertion loss and ripple).

Abstract: A surface magnetostatic wave device includes an Fe-containing garnet single crystal film grown on a gadolinium gallium garnet substrate. The crystallographic plane azimuth of the gadolinium gallium garnet substrate can be one of a (110) plane, a (100) plane, and a (211) plane. The device achieves both a reduced saturation magnetization and a reduced anisotropic magnetic field to thereby minimize the lowest frequency in the propagation band.