Tdk Corporation

Sei Kakinuma

Masahiro Onizuka

Yutaka Saito

Kouki Sato

Kensuke Ara

Ko Ito

Masaichi Miyano

Koh Itoh

Katsuya Iwai

A semiconductor magnetoresistance device having plural pairs of opposed short-circuiting electrodes ( ) on the opposed surfaces of a semiconductor magneto-sensitive layer ( ) shows a great resistance change relative to a magnetic flux density.

Semiconductor magnetoresistance device, making method and magnetic sensor

There is disclosed a BALUN transformer core material which has no magnetic permeability, contains a non-magnetic material and is not influenced by the frequency property of the magnetic permeability even in a high-frequency band. A BALUN transformer core which is obtained by pressing and sintering the BALUN transformer core material has no magnetic permeability and has a high specific resistance. A BALUN transformer which is obtained by applying a winding to the BALUN transformer core is a high-property BALUN transformer which can be operated in a high-frequency band of 600 MHz or more.

BALUN transformer core material, BALUN transformer core and BALUN

A core for inductance elements is formed of a sintered body of .alpha.-ferric oxide. The core has a flexural strength of at least 6 kgf/mm.sup.2 as measured by a three-point bending method, a specific resistance of at least 10.sup.6 .OMEGA..multidot.cm, a Vickers hardness of 800 to 1,500, and an iron content of 75 to 99.9 wt %, calculated as Fe.sub.2 O.sub.3. The core is produced by granulating, and forming a ferric iron powder, and holding a formed body for sintering at 950 to 1,500.degree. C. for 5 min. to 5 hours in an atmospheric environment.

Core for inductance elements and its production method

A ferrite core of the invention is useful for reducing the power loss of Ni--Cu--Zn ferrites, and so for particle accelerators, and power transformers. This core comprises a ferrite magnetic material containing as major components 47 to 50 mol % of iron oxide calculated as Fe.sub.2 O.sub.3, 10 to 25 mol % of nickel oxide calculated as NiO, 2 to 15 mol % of copper oxide calculated as CuO and 15 to 35 mol % of zinc oxide calculated as ZnO, and further containing as subordinate components 0.05 to 1.5 wt % of cobalt oxide calculated as CoO, 0.05 to 0.8 wt % of tungsten oxide calculated as WO.sub.3 and 0.03 to 0.5 wt % of bismuth oxide calculated as Bi.sub.2 O.sub.3, all based on the major components. Consequently, there is achieved a ferrite core having a power loss at 100.degree. C. of up to 210 kW/m.sup.3, and a power loss at 25.degree. C. of up to 140 kW/m.sup.3, as measured at f.multidot.Bm product=25 kTHz (f=1 to 10 MHz).

Growing community of inventors

Akita, Japan

Sei Kakinuma