Provided is a piezoelectric ceramics including crystal grains each including: a first region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at an asymmetrical position; and a second region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at a symmetrical position, and that is present inside the first region, wherein a ratio of a cross-sectional area of the second region to a cross-sectional area of the piezoelectric ceramics is 0.1% or less.

This ferrite sintered magnet comprises ferrite phases having a magnetoplumbite type crystal structure. This magnet comprises an element R, an element M, Fe, Co, B, Mn and Cr, the element R is at least one element selected from rare earth elements including Y, the element M is at least one element selected from the group consisting of Ca, Sr and Ba, with Ca being an essential element, and when an atomic composition of metallic elements is represented by R.sub.1-xM.sub.xFe.sub.m-yCo.sub.y, x, y and m satisfy formulae:
0.2≤x≤0.8  (1)
0.1≤y≤0.65  (2)
3≤m<14  (3). Additionally, a content of B is 0.1 to 0.4% by mass in terms of B.sub.2O.sub.3, a content of Mn is 0.15 to 1.02% by mass in terms of MnO, and a content of Cr is 0.02 to 2.01% by mass in terms of Cr.sub.2O.sub.3.

A method of manufacturing an electronic component capable of preventing entrance of a plating solution and a flux component at an interface to which an inner electrode of a ceramic element body is extended, and capable of forming an outer electrode of an arbitrary shape. A ceramic element body is made of a ceramic material containing a metal oxide, and part of an inner electrode is extended to extended surfaces of the ceramic element body. A base electrode is formed on each of the extended surfaces using a conductive paste to be connected to the inner electrode. Part of another surface of the ceramic element body adjacent to the extended surfaces is locally heated, and part of the metal oxide is reduced to form a reformed portion. A plating electrode is continuously formed over the base electrode and the reformed portion through a plating method to form outer electrodes.

A method of manufacturing an electronic component capable of preventing entrance of a plating solution and a flux component at an interface to which an inner electrode of a ceramic element body is extended, and capable of forming an outer electrode of an arbitrary shape. A ceramic element body is made of a ceramic material containing a metal oxide, and part of an inner electrode is extended to extended surfaces of the ceramic element body. A base electrode is formed on each of the extended surfaces using a conductive paste to be connected to the inner electrode. Part of another surface of the ceramic element body adjacent to the extended surfaces is locally heated, and part of the metal oxide is reduced to form a reformed portion. A plating electrode is continuously formed over the base electrode and the reformed portion through a plating method to form outer electrodes.

A method of manufacturing an electronic component capable of preventing entrance of a plating solution and a flux component at an interface to which an inner electrode of a ceramic element body is extended, and capable of forming an outer electrode of an arbitrary shape. A ceramic element body is made of a ceramic material containing a metal oxide, and part of an inner electrode is extended to extended surfaces of the ceramic element body. A base electrode is formed on each of the extended surfaces using a conductive paste to be connected to the inner electrode. Part of another surface of the ceramic element body adjacent to the extended surfaces is locally heated, and part of the metal oxide is reduced to form a reformed portion. A plating electrode is continuously formed over the base electrode and the reformed portion through a plating method to form outer electrodes.

A process for manufacturing ceramic-metal composite material, comprises dissolving ceramic powder into water to obtain an aqueous solution of ceramic; mixing metal powder having a multimodal particle size where largest particle size is one fourth of the minimum dimension of a device, with the aqueous solution of ceramic to obtain a powder containing ceramic precipitated on the surface of metal particles; mixing the powder containing ceramic precipitated on the surface of the metal particles, with ceramic powder having a particle size below 50 μm, to obtain a powder mixture; adding saturated aqueous solution of ceramic to the powder mixture to obtain an aqueous composition containing ceramic and metal; compressing the aqueous composition to form a disc of ceramic-metal composite material containing ceramic and metal; and removing water from the ceramic-metal composite material; wherein ceramic content of the disc is 10 vol-% to 35 vol-%. Alternatively, ceramic-ceramic composite material may be manufactured.

Disclosed are a ferrite green sheet comprising a pattern formed in a top surface of the ferrite green sheet, a sintered ferrite sheet, a ferrite composite sheet comprising the same, and a conductive loop antenna module. The pattern comprises a plurality of grooves, each groove has a width W and a rounded shape bottom having a radius of curvature of R, wherein a ratio of W to R (W:R) is in the range of 1:0.1 to 1:0.5.

Disclosed are a ferrite green sheet comprising a pattern formed in a top surface of the ferrite green sheet, a sintered ferrite sheet, a ferrite composite sheet comprising the same, and a conductive loop antenna module. The pattern comprises a plurality of grooves, each groove has a width W and a rounded shape bottom having a radius of curvature of R, wherein a ratio of W to R (W:R) is in the range of 1:0.1 to 1:0.5.

Provided is a ferrite sintered magnet including: magnetoplumbite type ferrite crystal grains; and a two-grain boundary interposed between the ferrite crystal grains. The two-grain boundary contains Ca and La, and an atomic ratio Ca/La at the two-grain boundary is 0.3 to 3.0.

A method for producing MnZn-ferrite comprising Fe, Mn and Zn as main components, and at least Co, Si and Ca as sub-components, the main components in the MnZn-ferrite comprising 53-56% by mol (as Fe.sub.2O.sub.3) of Fe, and 3-9% by mol (as ZnO) of Zn, the balance being Mn as MnO, comprising the step of sintering a green body to obtain MnZn-ferrite; the sintering comprising a temperature-elevating step, a high-temperature-keeping step, and a cooling step; the high-temperature-keeping step being conducted at a keeping temperature of higher than 1050° C. and lower than 1150° C. in an atmosphere having an oxygen concentration of 0.4-2% by volume; the oxygen concentration being in a range of 0.001-0.2% by volume during cooling from 900° C. to 400° C. in the cooling step; and the cooling speed between (Tc+70)° C. and 100° C. being 50° C./hour or more, wherein Tc represents a Curie temperature (° C.) calculated from % by mass of Fe.sub.2O.sub.3 and ZnO.