A composite body including a substrate and a forming portion which is composed of a composite phase containing a perovskite oxide and a metal oxide different from the perovskite oxide and which is formed on the substrate. The composite body may be a composite body manufactured by a manufacturing method including a forming step of firing in an oxidizing atmosphere, a laminated body in which an inorganic raw material powder containing a compound powder and a metal powder is disposed on a substrate so as to form a forming portion composed of a composite phase containing a perovskite oxide and a metal oxide different from the perovskite oxide on the substrate.

A composite body including a substrate and a forming portion which is composed of a composite phase containing a perovskite oxide and a metal oxide different from the perovskite oxide and which is formed on the substrate. The composite body may be a composite body manufactured by a manufacturing method including a forming step of firing in an oxidizing atmosphere, a laminated body in which an inorganic raw material powder containing a compound powder and a metal powder is disposed on a substrate so as to form a forming portion composed of a composite phase containing a perovskite oxide and a metal oxide different from the perovskite oxide on the substrate.

A joined body 20 includes a first member 21, a second member 22, and a joint portion 30 which is formed from an oxide ceramic containing a Fe.sub.3O.sub.4 phase in which a solute component capable of forming a spinel-type oxide with Fe is solid-dissolved and which joins the first member 21 and the second member 22.

A membrane electrode assembly includes an electrode consisting of at least one compound selected from the group consisting of lanthanum strontium cobalt complex oxide, lanthanum strontium cobalt iron complex oxide, and lanthanum strontium iron complex oxide, or consisting of a composite of the at least one compound and an electrolyte material, and a first solid electrolyte membrane represented by a composition formula of BaZr.sub.1xLu.sub.xO.sub.3 (0<x<1). The electrode is in contact with the first solid electrolyte membrane.

The fuel cell according to the present invention has an anode, a cathode and a solid electrolyte layer. The cathode contains a perovskite oxide as a main component. The perovskite oxide is expressed by the general formula ABO.sub.3 and including La and Sr at the A site. The solid electrolyte layer is disposed between the anode and the cathode. The cathode has a surface on opposite side to the solid electrolyte layer. A first ratio of a Sr concentration relative to an La concentration is less than or equal to 4 times a second ratio of the Sr concentration relative to the La concentration. The first ratio is detected by use of X-ray photoelectron spectroscopy on the surface of the cathode. The second ratio of a Sr concentration relative to a La concentration is detected by use of X-ray photoelectron spectroscopy on an exposed surface. The exposed surface is exposed by surface processing of the surface. The exposed surface is positioned within 5 nm of the surface in relation to a direction of thickness.

The embodiments of the present invention disclose a method for synthesizing ceramic composite powder and ceramic composite powder, pertaining to the technical field of inorganic non-metallic materials. Among them, the method includes preparing an aqueous slurry of ceramic raw materials, the aqueous slurry including ceramic raw material, water and low polymerization degree organometallic copolymer, the ceramic raw material including at least two components; adding a crosslinking coagulant into the aqueous slurry to obtain a gel; dehydrating and drying the gel to obtain the dried gel; heating the dried gel to the synthesizing temperature of the ceramic composite powder and conducting the heat preservation to obtain ceramic composite powder or ceramic composite base powder; conducting secondary doping on ceramic composite base powder to obtain the ceramic composite powder. The multi-component ceramic composite powder prepared by the embodiments of the present invention has uniformly dispersed each component and low synthesizing temperature.

A gas sensor, characterized by having an electrode formed of a conductive oxide sintered body which contains a primary phase formed of a perovskite oxide containing at least La, Fe, and Ni; and a secondary phase formed of an La.sub.4M.sub.3O.sub.10 phase or an La.sub.3M.sub.2O.sub.7 phase (M=Co, Fe, Ni), wherein the conductive oxide sintered body has a conductivity of 300 S/cm or higher at room temperature.

A honeycomb structural body 40 includes: a partition wall 48 formed of a porous ceramic which forms and defines a plurality of cells 47 each functioning as a flow path of a fluid and extending from one end surface to the other end surface; and an outer circumference wall 49 formed along the outermost circumference, where an oxide ceramic containing a Fe.sub.3O.sub.4 phase in which a solute component capable of forming a spinel-type oxide with Fe is solid-dissolved is formed.

A liquid-ejecting head includes a pressure-generating chamber communicating with a nozzle opening, and a piezoelectric element. The piezoelectric element has piezoelectric layer contains a perovskite complex oxide containing Bi, La, Fe, and Mn and can undergo electric-field-induced phase transition.

Disclosed are a microwave ferrite material for a miniaturized circulator, and a preparation method therefor. The microwave ferrite material has a garnet structure as a main phase, and has a chemical formula as follows: Y.sub.3-aCa.sub.aZr.sub.bV.sub.cFe.sub.5-b-cO.sub.12. The preparation method comprises: mixing raw materials according to a stoichiometric ratio to obtain a raw material mixture; performing first wet ball milling on the raw material mixture to obtain a first slurry; sequentially drying and pre-sintering the first slurry to obtain first powder; performing second wet ball milling on the first powder to obtain a second slurry; sequentially drying and granulating the second slurry to obtain second powder; and sequentially forming and sintering the second powder to obtain a microwave ferrite material. Accordingly, the bandwidth of a miniaturized lumped circulator is widened so that the miniaturized lumped circulator meets 5G communication requirements; moreover, the device loss is reduced, and the communication quality is improved.