Kyocera Corporation

Masahiro Nishigaki

Daisuke Fukuda

Kiyoshi Matsubara

Hideyuki Osuzu

Jun Ueno

Katsuyoshi Yamaguchi

Kousei Kamigaki

Kenichi Iwasaki

Shota Mukoyama

Hiroaki Mino

Masaaki Nagoya

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.

Capacitor

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&#xb0; C.

Multilayer ceramic capacitor

A dielectric ceramic and a capacitor comprising the dielectric ceramic are disclosed. The dielectric ceramic has a high dielectric constant that is stable over temperature, and has a small spontaneous polarization. The capacitor can reduce audible noise caused by an electrically induced strain in a power supply circuit.

Dielectric ceramics and capacitor

The invention provides a multilayer ceramic capacitor comprising a capacitor body composed by alternately layering dielectric layers and inner electrode layers. Accordingly, the multilayer ceramic capacitor has high relative permittivity and is high the temperature property and highly accelerated life test property.

Multilayer ceramic capacitor and production method of the same

Provided is a multilayer ceramic capacitor having a capacitor body formed by alternately laminating a dielectric layer and an internal electrode layer, and an external electrode formed on both ends of the capacitor body. The dielectric layer has at least two type of barium titanate crystal grains that differ from one another in at least one selected from Ca composition concentration, Sr composition concentration, and Zr composition concentration, and a grain boundary phase. If this multilayer ceramic capacitor employs, as a dielectric layer, a dielectric ceramic that contains barium titanate crystal grains in which part of Ba is substituted by Ca, Sr, or Zr, it is capable of suppressing the grain growth of crystal grains, and improving relative dielectric constant, temperature characteristic, and high-temperature load test characteristic, for example, in high-volume manufacturing using a tunnel type large kiln.

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Kirishima, Japan

Masahiro Nishigaki