Abstract: The dielectric layers are formed from a dielectric porcelain formed from crystal particles containing barium titanate as a main component and containing a rare earth element, and the crystal particles have, in a particle boundary vicinity, a low concentration region in which the concentration of the rare earth element is lower than the concentration of the rare earth element in an inside. The crystal particles further contain vanadium, and the low concentration region contains a larger amount of the vanadium than the amount of the vanadium in the inside. The crystal particles further contain magnesium and manganese, and the magnesium and the manganese have a concentration gradient that is at a maximum at the particle boundary vicinity and that lowers toward the inside.

Abstract: The dielectric layers are formed from a dielectric porcelain formed from crystal particles containing barium titanate as a main component and containing a rare earth element, and the crystal particles have, in a particle boundary vicinity, a low concentration region in which the concentration of the rare earth element is lower than the concentration of the rare earth element in an inside. The crystal particles further contain vanadium, and the low concentration region contains a larger amount of the vanadium than the amount of the vanadium in the inside. The crystal particles further contain magnesium and manganese, and the magnesium and the manganese have a concentration gradient that is at a maximum at the particle boundary vicinity and that lowers toward the inside.

Abstract: Disclosed is a multilayer ceramic capacitor which is formed by alternately laminating (i) dielectric layers composed of a dielectric ceramic and (ii) internal electrode layers. The dielectric ceramic is composed of crystal grains mainly composed of barium titanate, while containing predetermined amounts of magnesium, vanadium, manganese and terbium, and at least one rare earth element selected from yttrium, dysprosium, holmium and erbium. In an x-ray diffraction chart of the dielectric ceramic, the diffraction intensity of the (200) plane indicating cubic barium titanate is higher than the diffraction intensity of the (002) plane indicating tetragonal barium titanate. The dielectric ceramic has a Curie temperature of 110-120° C.

Abstract: A dielectric ceramic exhibiting a high dielectric constant is provided. The relative dielectric constant of the dielectric ceramic is stable with respect to temperature dependence and exhibits insulation resistance having a reduced voltage dependence. The dielectric ceramic of the invention can be used to form a multilayer ceramic capacitor that has a long life.

Abstract: A crystal constituting a dielectric porcelain, comprised of a first crystal group composed of crystal grains of 0.2 atomic % or less calcium concentration and a second crystal group composed of crystal grains of 0.4 atomic % or more calcium concentration, wherein the ratio of concentration of each of magnesium and a first rare earth element contained in a center portion to that contained in a surface layer portion of crystal grains constituting the first crystal group is greater than the corresponding concentration ratio of crystal grains constituting the second crystal group, and wherein on a polished surface resulting from polishing of the surface of the dielectric porcelain, when the area of crystal grains of the first crystal group is referred to as a and the area of crystal grains of the second crystal group referred to as b, the ratio of b/(a+b) is in the range of 0.5 to 0.8.

Abstract: The invention relates to a multilayer ceramic capacitor having dielectric layers and internal electrode layers disposed alternately. The dielectric layers include a dielectric ceramic containing barium titanate as a main component, and also calcium, magnesium, vanadium, manganese, and a rare-earth element. Crystals constituting the dielectric ceramic are constituted by grains containing barium titanate as their main component and containing calcium in a concentration of 0.2 atomic % or less or containing the calcium in a concentration of 0.4 atomic % or more. The crystals grains are also distinct in their relative distributions of magnesium and rare-earth elements between the center of the grain and the surface of the grain. Finally, the relative areas of the two kinds of crystals observed in the plane of a polished surface of the dielectric ceramic are described by a ratio b/(a+b), which is 0.5 to 0.8.

Abstract: Disclosed is a multilayer ceramic capacitor which is formed by alternately laminating (i) dielectric layers composed of a dielectric ceramic and (ii) internal electrode layers. The dielectric ceramic is composed of crystal grains mainly composed of barium titanate, while containing predetermined amounts of magnesium, vanadium, manganese and terbium, and at least one rare earth element selected from yttrium, dysprosium, holmium and erbium. In an x-ray diffraction chart of the dielectric ceramic, the diffraction intensity of the (200) plane indicating cubic barium titanate is higher than the diffraction intensity of the (002) plane indicating tetragonal barium titanate. The dielectric ceramic has a Curie temperature of 110-120° C.

Abstract: A crystal constituting a dielectric porcelain, comprised of a first crystal group composed of crystal grains of 0.2 atomic % or less calcium concentration and a second crystal group composed of crystal grains of 0.4 atomic % or more calcium concentration, wherein the ratio of concentration of each of magnesium and a first rare earth element contained in a center portion to that contained in a surface layer portion of crystal grains constituting the first crystal group is greater than the corresponding concentration ratio of crystal grains constituting the second crystal group, and wherein on a polished surface resulting from polishing of the surface of the dielectric porcelain, when the area of crystal grains of the first crystal group is referred to as a and the area of crystal grains of the second crystal group referred to as b, the ratio of b/(a+b) is in the range of 0.5 to 0.8.

Abstract: [Problems] To provide a multilayered ceramic capacitor which in a high-temperature loading test, can be inhibited from decreasing in insulation resistance with time and which can have high insulating properties even when produced without via a reoxidation step. [Means for Solving Problems] The multilayered ceramic capacitor is formed by alternately superposing dielectric layers made of dielectric porcelain and inner-electrode layers. The dielectric porcelain is constituted of first crystals comprising crystal particles comprising barium titanate as the main component and having a calcium concentration of 0.2 at. % or lower and second crystals comprising crystal particles having a calcium concentration of 0.4 at. % or higher.

Abstract: A dielectric ceramics comprising a high dielectric constant is disclosed. The dielectric ceramics also comprises a relative dielectric constant with a stable temperature dependence and an insulation resistance with a reduced voltage dependence. The dielectric ceramics can be used to form a multilayer ceramic capacitor that has a long life.

Abstract: The present invention relates to an alumina-based ceramic material mainly comprising alumina, produced by shaping mixture of manganese-titanium composite oxide and a vanadium oxide and sintering the resulting shaped article, and a production method therefor. The alumina-based ceramic material in the present invention can be applied to uses for dielectric porcelain, dielectric antenna and dielectric resonator and a supporting stand therefor, dielectric filter, dielectric duplexer, and communication device.