Tdk Corporation

Yuji Sezai

Saori Takeda

Toshihiko Kaneko

Yuki Yamashita

Katsushi Yasuhara

Masahiko Watanabe

Hiroki Uchiyama

Masahito Furukawa

Masanori Kosuda

Shirou Ootsuki

Raitarou Masaoka

Kenya Takagawa

Ippou Hirai

A coil device, in which an air-core coil of a cylindrical shape is buried in a core including a magnetic powder and a resin, showing, CV value of the below described cross sectional areas, SAto SA, 0.55 or less, when an outer diameter of the air-core coil is 'a', an inner diameter of the same is 'a', and a distance between a surface of the core perpendicular to a direction of winding axis and an end of the air-core coil in the direction of winding axis is &#x201c;h&#x201d;, is provided. The coil device is superior in DC superimposing characteristic while suppressing the magnetic saturation.

Coil device

A dielectric composition contains major components that are an A-group containing major components that are at least two selected from the group consisting of Ba, Ca, and Sr and a B-group which contains a major component that is selected from Zr and Ti and which contains at least Zr. The dielectric composition contains an amorphous substance containing the A-group and the B-group and a crystalline substance containing the A-group and the B-group. In the dielectric composition, the inequality 0.5&#x2266;&#x3b1;&#x2266;1.5 holds, where &#x3b1; is the molar ratio of the A-group to the B-group.

Dielectric composition and electronic component

A dielectric composition containing a crystalline phase represented by a general formula of BiSiOand a crystalline phase represented by a general formula of BiSiOas the main components. The dielectric composition contains preferably 5 mass % to 99 mass % of the BiSiOcrystalline phase, and more preferably 30 mass % to 99 mass %.

Dielectric composition, dielectric film, and electronic component

A dielectric film contains as a main component a dielectric composition represented by the general formula (BaCa)(TiZr)Owherein 0.001&#x2266;x&#x2266;0.400, 0.001&#x2266;y&#x2266;0.400, and 0.900&#x2266;z&#x3c;0.995. In an X-ray diffraction pattern of the dielectric composition, the dielectric composition has the relation 0.00&#xb0;&#x2266;2&#x3b8;&#x2212;2&#x3b8;&#x3c;0.20&#xb0; between (001) plane diffraction peak position 2&#x3b8;of a tetragonal structure represented by the general formula and (100) plane diffraction peak position 2&#x3b8;of a cubic structure represented by the general formula.

Dielectric film and dielectric element

An Mn&#x2014;Zn ferrite wherein 0 to 5000 ppm of a Co oxide in a CoOconversion is contained in a basic component constituted by FeO: 51.5 to 57.0 mol % and ZnO: 0 to 15 mol % (note that 0 is not included) wherein the rest is substantially constituted by MnO; and a value &#x3b1; in a formula (1) below in said ferrite satisfies &#x3b1;&#x2267;0.93.&#x3b1;=((Fe&#x2212;Mn&#x2212;Co)&#xd7;(4.291.912.192.01))/(()&#xd7;100)&#x2003;&#x2003;formula (1).Note that in the formula (1), (Fe&#x2212;Mn&#x2212;Co): [wt %], A: FeO[mol %], B: MnO [mol %], C: ZnO [mol %] and D: CoO [mol %]. According to the present invention, a highly reliable Mn&#x2014;Zn ferrite used as a magnetic core of a power supply transformer, etc. of a switching power supply, etc., having a small core loss in a wide temperature range, furthermore, exhibiting a little deterioration of core loss characteristics under a high temperature (in a high temperature storage test) and having excellent magnetic stability, a transformer magnetic core and a transformer can be provided.

Mn-Zn ferrite, transformer magnetic core and transformer

An Mn&mdash;Zn based ferrite composition having a main component comprised of Fe O : 51.5 to 54.5 mol %, ZnO: 19.0 to 27.0 mol % and the rest of substantially MnO and a first sub component comprised of 0.002 to 0.040 wt % of SiO , 0.003 to 0.045 wt % of CaO and 0.010 wt % or less of P with respect to 100 wt % of the main component. In a magnetic core for a transformer comprised of this composition, the THD of the transformer becomes &minus;84 dB or less in a broad frequency band, so it can be preferably used as a magnetic core, for example, for an xDSL modem transformer.

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Tokyo, Japan

Yuji Sezai