An oxide superconductor of an embodiment includes an oxide superconductor layer having a continuous Perovskite structure including rare earth elements, barium (Ba), and copper (Cu). The rare earth elements include a first element which is praseodymium, at least one second element selected from the group consisting of neodymium, samarium, europium, and gadolinium, at least one third element selected from the group consisting of yttrium, terbium, dysprosium, and holmium, and at least one fourth element selected from the group consisting of erbium, thulium, ytterbium, and lutetium. When the number of atoms of the first element is N(PA), the number of atoms of the second element is N(SA), and the number of atoms of the fourth element is N(CA), 1.5(N(PA)+N(SA))N(CA) or 2(N(CA)N(PA))N(SA) is satisfied.

Provided are a macroporous titanium compound monolith and a production method thereof, the macroporous titanium compound monolith having a framework that is composed of a titanium compound other than titanium dioxide, having controlled macropores, and having electron conductivity, the titanium compound being oxygen-deficient titanium oxide, titanium oxynitride, or titanium nitride. Provided is a method including: placing a macroporous titanium dioxide monolith and a metal having titanium-reducing ability in a container, the macroporous titanium dioxide monolith having a co-continuous structure of a macropore and a framework that is composed of titanium dioxide; creating a vacuum atmosphere or an inert gas atmosphere within the container; and heating the monolith and the metal to cause gas-phase reduction that removes oxygen atom from the titanium dioxide composing the monolith by the metal acting as an oxygen getter, thereby obtaining a macroporous oxygen-deficient titanium oxide monolith having a co-continuous structure of the macropore and a framework that is composed of oxygen-deficient titanium oxide, the macroporous oxygen-deficient titanium oxide monolith having electron conductivity derived from the oxygen-deficient titanium oxide.

An oxide superconductor of an embodiment includes an oxide superconductor layer having a continuous Perovskite structure containing rare earth elements, barium (Ba), and copper (Cu). The rare earth elements contain a first element which is praseodymium (Pr), at least one second element selected from the group consisting of neodymium (Nd), samarium (Sm), europium (Eu), and gadolinium (Gd), at least one third element selected from the group consisting of yttrium (Y), terbium (Tb), dysprosium (Dy), and holmium (Ho), and at least one fourth element selected from the group consisting of erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

Provided is a Li-containing phosphoric-acid compound sintered body of both high relative density and very small crystal grain diameter with reduced incidence of defects (voids) such as air holes, the Li-containing phosphoric-acid compound sintered body causing a Li-containing phosphoric-acid compound thin film useful as a solid electrolyte for a secondary cell or the like to be stabilized without any incidence of target cracking or irregular electrical discharge, and offering high-speed film-forming capability. This Li-containing phosphoric-acid compound sintered body contains no defects measuring 50 m or larger within a 1 mm.sup.2 cross-sectional region in the interior thereof, while having an average crystal grain diameter of no more than 15 m and a relative density of at least 85%.

A piezoelectric material that has good insulating properties and piezoelectricity and is free of lead and potassium and a piezoelectric element that uses the piezoelectric material are provided. The piezoelectric material contains copper and a perovskite-type metal oxide represented by general formula (1): (1?x){(Na.sub.yBa.sub.1?z)(Nb.sub.zTi.sub.1?z) O.sub.3}-xBiFeO.sub.3 (where 0<x?0.015, 0.80?y?0.95, and 0.85 ?z?0.95). In the piezoelectric material, 0.04 mol % or more and 2.00 mol % or less of Cu is contained relative to 1 mol of the perovskite-type metal oxide. Also provided is a piezoelectric element that includes a first electrode, a piezoelectric material, and a second electrode, in which the piezoelectric material described above is used as the piezoelectric material.

A solid ceramic electrolyte may include an ion-conducting ceramic and at least one grain growth inhibitor. The ion-conducting ceramic may be a lithium metal phosphate or a derivative thereof. The grain growth inhibitor may be magnesia, titania, or both. The solid ceramic electrolyte may have an average grain size of less than about 2 microns. The grain growth inhibitor may be between about 0.5 mol. % to about 10 mol. % of the solid ceramic electrolyte.

A sintered bead has a chemical composition, as mass percentages on the basis of the oxides of ZrO.sub.2+HfO.sub.2+Y.sub.2O.sub.3+CeO.sub.2: balance to 100%; 0%Al.sub.2O.sub.31.5%; CaO2%; and oxides other than ZrO.sub.2, HfO.sub.2, Y.sub.2O.sub.3, CeO.sub.2, Al.sub.2O.sub.3 and CaO: 5%. The contents of Y.sub.2O.sub.3 and CeO.sub.2, as molar percentages on the basis of the sum of ZrO.sub.2, HfO.sub.2, Y.sub.2O.sub.3 and CeO.sub.2, are such that 1.3%Y.sub.2O.sub.32.5%, in particular 1.3%Y.sub.2O.sub.3<1.8%, and 0.1%CeO.sub.21.7%, in particular 0.5%CeO.sub.21.7%, in particular 0.9%<CeO.sub.21.7%. The chemical composition has the following crystalline phases, as mass percentages on the basis of the crystalline phases and for a total of 100%: stabilized zirconia: balance to 100%; monoclinic zirconia: 15%; and crystalline phases other than stabilized zirconia and monoclinic zirconia: <7%, with the proviso that: Y.sub.2O.sub.3<1.8% with the proviso that 0.5%CeO.sub.2, and/or 0.9%<CeO.sub.21.7%, and/or 10%<monoclinic zirconia15%.

Thermoelectric materials based on tetrahedrite structures for thermoelectric devices and methods for producing thermoelectric materials and devices are disclosed.

A ferrite composition is provided containing Ba, Co, and Ir and having a Z-type hexaferrite phase and a Y-type hexaferrite phase. The ferrite composition has the formula Ba.sub.3Co.sub.(2-x)Ir.sub.xFe.sub.(24-2x)O.sub.41 where x=0.05-0.20. The composition has equal or substantially equal values of permeability and permittivity while retaining low magnetic and dielectric loss factors. The composition is suitable for ultrahigh frequency applications such as high frequency and microwave antennas.

A transparent sintered body having fewer air bubble-derived defects is provided. More specifically, a method is provided of producing a ceramic molded product including at least a step of pressure-molding ceramic granules having a Hausner ratio, which is a quotient obtained by dividing a tapped bulk density by a loose bulk density, of 1.0 or more but not more than 1.2. Also provided is a method of producing a transparent sintered body including at least each of the steps of the above method to obtain a ceramic molded product and a step of heating and sintering the resulting ceramic molded product. The transparent sintered body has a linear transmittance of 78% or more at a wavelength of 600 nm to 2000 nm inclusive except for an element-derived characteristic absorption wavelength.