Abstract: To use a media agitating mill of a wet internal circulation type when grinding materials, and offer oxide magnetic materials and coils in which influences of ZrO2 and Y2O3 mixing when using partially stabilized zirconia as media beads are improved. The magnetic materials and coils are characterized in that Fe2O3, ZnO, NiO and CuO are main components, and Y2O3, ZrO2 and Bi2O3 are contained with respect to these main components, where an amount of Y2O3 is 0.007 to 0.028 wt % for the total amount, an amount of ZrO2 is 0.12 to 0.55 wt % therefor and an amount of Bi2O3 is 0.03 to 10.12 wt % for the same.

Abstract: The present invention provides a Mn—Zn ferrite having an electrical resistivity exceeding 1 &OHgr;m order and having a high initial permeability of 3000 or more at 100 kHz and 100 or more at 10 MHz. The main components of the Mn—Zn ferrite are 44.0 to 49.8 mol % Fe2O3, 15.0 to 26.5 mol % ZnO, 0.02 to 1.00 mol % Mn2O3 and the remainder MnO. The Mn—Zn ferrite is enabled to be used in a wide frequency region from 100 kHz to 10 MHz by limiting Fe2O3 content to less than 50 mol % that is the stoichiometric composition and inhibiting formation of Mn2O3.

Abstract: This invention relates to the formula and preparation method for a multi-layer chip inductor material used in very high frequencies. The main composition of this material is planar hexagonal soft magnetic ferrite, and ingredient is low temperature sintering aid. Preparation method is a synthetic method of solid phase reaction. The sintering aid is prepared by secondary doping. By the process of ball grinding, drying, pre-calcining, ball grinding, drying, granulating, forming, sintering, and so forth, very high frequency inductor material of superior quality is obtained, realizing low temperature sintering under a temperature lower than 900° C. This invention is of low cost, high performance, suitable for multi-layer chip inductors at very high frequencies of 300M-800 MHz.

Abstract: In the method for manufacturing ferrite type permanent magnets according to the formula M1-xRxF12-yTyO19:

Abstract: Nickel composite particles having a layer of a nickel-containing spinel on at least a part of the surface of nickel particles, or nickel composite particles having an oxide layer of metals other than nickel on at least a part of the surface of nickel particles and a layer of a nickel-containing spinel at an interface between the nickel particles and the metal oxide layer. The nickel composite particles are produced by forming fine liquid droplets from a solution containing (a) at least one thermally decomposable nickel compound and (b) at least one thermally decomposable metal compound capable of forming a spinel together with nickel; and heating the liquid droplets at a temperature higher than the decomposition temperatures of the compound (a) and (b) to nickel particles and simultaneously deposit a nickel-containing spinel layer, or further a metal oxide layer on the spinel layer.

Abstract: A magnetic ferrite composition including at least one of Mg, Ni, Cu, Zn, Mn, and Li and having a content of carbon within a predetermined range, for example, over 9.7 weight ppm to less than 96 weight ppm. The composition may be used as the magnetic core for an inductor, transformer, coil, etc. used for radios, televisions, communication devices, office automation equipment, switching power sources, and other electronic apparatuses or magnetic heads for video apparatuses or magnetic disk drives or other electronic components.

Abstract: A magnetic substance having the maximum value of complex permeability in quasi-microwave range is provided for suppressing a high frequency noise in a small-sized (electronic apparatus. The magnetic substance is of a magnetic composition comprising M, X and Y, where M is a metallic magnetic material consisting of Fe, Co, and/or Ni, X being element or elements other than M and Y, and Y being F, N, and/or O. The M-X-Y magnetic composition has a concentration of M in the composition so that said M-X-Y magnetic composition has a saturation magnetization of 35-80% of that of the metallic bulk of magnetic material comprising M alone. The magnetic composition has the maximum &mgr;″max of complex.

Abstract: A magnetic ferrite composition including at least one of Mg, Ni, Cu, Zn, Mn, and Li and having a content of carbon within a predetermined range, for example, over 9.7 weight ppm to less than 96 weight ppm. The composition may be used as the magnetic core for an inductor, transformer, coil, etc. used for radios, televisions, communication devices, office automation equipment, switching power sources, and other electronic apparatuses or magnetic heads for video apparatuses or magnetic disk drives or other electronic components.

Abstract: The ferrite magnet powder of the present invention is magnet powder having, as the major phase, a La—Co magnetoplumbite ferrite where La and Co are substituted for Sr and Fe, respectively, represented by (1−x)SrO.(x/2)La2O3.(n−y/2)Fe2O3.yMO wherein x, y, and n represent mole ratios and satisfy 0.22−0.02≦x≦0.22+0.02, 0.18−0.02≦y≦0.18+0.02, and 5.2≦n≦6.0, where x>y.

Abstract: Magnetorheological fluid concentrates are provided which contain a substantially dry mixture of magnetic-responsive powder and a thixotropic agent. The concentrates may be mixed with an aqueous or an organic carrier fluid to form magnetorheological fluids.

Abstract: The present invention provides a Mn—Zn ferrite having an electrical resistivity exceeding 1 &OHgr;m order and a low core loss in a high frequency region exceeding 1 MHz. A basic component composition of the Mn—Zn ferrite includes 44.0 to 49.8 mol % of Fe2O3, 6.0 to 15.0 mol % of ZnO (15.0 mol % is excluded), 0.1 to 3.0 mol % of CoO, 0.02 to 1.20 mol % of Mn2O3, and the remainder of MnO. The Mn—Zn ferrite achieves desired purposes by controlling Fe2O3 content to a range less than 50 mol % that is the stoichiometric composition, adding a proper amount of CoO, restraining amount of Mn2O3 formation to 1.20 mol % or less, and further setting their average grain sizes to less than 10 &mgr;m.

Abstract: Porous composite particles contain 80 to 98% by weight of a filling material and 2 to 20% by weight of carbon, and have an average pore diameter of not more than 5 nm when measured with respect to pores existing in both the surface and inside portions thereof, an average particle size of 1 to 1,000 &mgr;m and a specific surface area of 45 to 200 m2/g. These porous composite particles individually contain the filling material in as large an amount as possible, so they have not only a high catalytic but also a high adsorption ability, thereby exhibiting an excellent catalytic activity.

Abstract: MnZn ferrite comprises a main component comprising iron oxide 52.5 to 54.0 mol % in terms of Fe2O3, zinc oxide 7.7 to 10.8 mol % in terms of ZnO, and manganese oxide of the remaining, and sub-components of silicon oxide 60 to 140 ppm in terms of SiO2 and calcium oxide 350 to 700 ppm in terms of CaO, and further contains nickel oxide 4500 ppm or lower (not including 0) in terms of NiO.

Abstract: A magnetic composition comprised of cobalt ferrite nanoparticles dispersed in an ionic exchange resin.

Abstract: This invention provides a Mn—Zn ferrite which has a high electrical resistance and can sufficiently satisfy the use in a high frequency region exceeding 1 MHz. This invention further provides a production process of the Mn—Zn ferrite in which mixed powder whose components are adjusted so as to have a basic component composition containing 44.0 to 50.0 mol% Fe2O3, 4.0 to 26.5 mol % ZnO, 0.1 to 8.0 mol % one or two from TiO2 and SnO2 and the remainder consisting of MnO, and further to contain 0.01 to 2.00 mass % one or more of CoO, NiO, and MgO as additive is pressed, then sintered and cooled in the air or in an atmosphere containing some amount of oxygen.

Abstract: A ferrite material based on nickel, copper and zinc has the following formula: NixZnyCuzCo&egr;Fe2±&dgr;O4 in which: x+y+Z+&egr;=1±&dgr; &dgr;≦0.05 0.04≦&egr; 0.05≦z≦0.35 A material of this kind has the advantage of showing reduced losses.

Abstract: The present invention provides a Mn—Zn ferrite having an electrical resistivity exceeding 1 &OHgr;m order and having a high initial permeability of 4000 or more at 100 kHz and 100 or more at 10 MHz. The main components of the Mn—Zn ferrite include 44.0 to 49.8 mol % Fe2O3, 15.0 to 26.5 mol % ZnO, 0.1 to 3.0 mol % CoO, 0.02 to 1.00 mol % Mn2O3, and the remainder MnO. The Mn—Zn ferrite can be used in a wide frequency region of 100 kHz to 10 MHz by limiting Fe2O3 content to a range of less than 50 mol %, that is the stoichiometric composition, inhibiting formation of Mn2O3 and adding a proper amount of CoO.

Abstract: A manganese-zinc base ferrite containing iron oxide, manganese oxide and zinc oxide as main components in amounts calculated as Fe2O3, MnO and ZnO, respectively, Fe2O3 50 to 56 mol %, MnO 21 to 27 mol %, and ZnO 20 to 26 mol %, and 0.0003 to 0.003% by weight calculated as P of phosphorus as an auxiliary component, and having a mean grain size from more than 50 &mgr;m to 200 &mgr;m.

Abstract: The present invention relates to methods of producing synthetic crystals (typically minerals) or comparable inorganic compounds by reactions of metal salts and metal oxyhydroxides under near-critical, critical or supercritical solvent conditions, avoiding thereby many of the difficulties associated with conventional solid state or wet chemistry synthesis. The metal oxyhydroxides are typically divalent or trivalent metals and the preferred solvent is typically (but not exclusively) water under near-critical, critical or supercritical conditions. The crystals so produced have a controlled particle size distribution. The crystals produced by the present invention also have morphologies with favorable properties for compaction into green bodies for subsequent sintering into near-net-shapes, approaching maximum theoretical densities. Avoidance of noxious by-products is another advantage of the present synthetic methods.

Abstract: Granule for forming ferrite is provided by mixing powders of ferrite raw material, polyvinyl alcohol as a binder and polyethylene glycol added as plasticizer and having molecular weight being 1000 to 6000, and forming granules.

Abstract: A method of producing a single crystal of the composition M3NbGa3Si2O14 (where M is an alkaline earth metal) comprising growing in a lattice direction inclined at an angle of 50.8 to 90 degrees from a [001] axis. The single crystal obtained in this way may be suitably used as a component of a resonator, filter, or other various piezoelectric elements.

Abstract: A process for producing Mn—Zn ferrite having large electrical resistance and being durable to the use in high frequency region exceeding 1 MHz easily and at low cost is disclosed. The process comprises pressing a mixed powder comprising a composition of 44.0 to 50.0 mol % of Fe2O3, 4.0 to 26.5 mol % of ZnO, 0.1 to 8.0 mol % of at least one member selected from the group consisting of TiO2 and SnO2, and the remainder being MnO, and if desired 0.1 to 16.0 mol % of CuO, sintering the resulting green compact in the air or an atmosphere containing an appropriate amount of oxygen, and then cooling the green compact, thereby securing the estimated high initial permeability even in a high frequency region of 1 MHz or more.

Abstract: There is disclosed a magnetic ferrite material obtained by calcining a raw material, forming a calcined powder into a desired shape and sintering to contain Fe2O3, MnO and ZnO as main components, the magnetic ferrite material with a low power loss is realized by setting the coefficient of variation (CV value) of the content of a Ca component precipitated along a grain boundary in a range of 1 to 60%, and the magnetic ferrite material is manufactured by calcining the raw material containing Fe2O3, MnO and ZnO as the main components to obtain the calcined powder in which that the S component content is in a range of 1 to 200 ppm, and forming the calcined powder into the desired shape and sintering.

Abstract: Provided are a method for preparing an Ni—Cu—Zn ferrite powder having excellent sinterability at a lower temperature, and a method for producing a laminated chip inductor from the above ferrite powder. The method for preparing the ferrite powder is a method for the preparation of a soft magnetic ferrite powder composed of Fe, Ni, Cu and Zn as main components, and comprises the step of allowing an organic additive to be present in a slurry containing a calcined product of a starting powder and water, wherein the organic additive is an organic compound having a hydroxyl group and a carboxyl group or a neutralization salt or lactone thereof, or the organic additive is an organic compound having a hydroxymethylcarbonyl group, an organic compound having an enol type hydroxyl group dissociable as an acid or a salt thereof.

Abstract: The present invention provides a magnetic film expressed by a composition formula TaMbXcNdOe (T is a magnetic metal such as Fe, M is an alkaline earth metal such as Be, Mg, and Ca, and X is at least one selected from the group consisting of Y, Ti, Zr, Hf, V, Nb, Ta and lanthanoid), where a+b+c+d+e=100, 45 ≦a≦85, 5.5≦b≦28, 0.5≦c≦16, 6≦b+c≦28.5, 0.4 <b/c ≦56, 0≦d≦10, and 8≦d+e≦40. The magnetic film comprises mainly metal magnetic crystal grains having an average crystal grain diameter of not more than 15 nm and a grain boundary product. The grain boundary product substantially separates the metal magnetic crystal grains. The main component of the metal magnetic crystal grains is the T. The grain boundary product contains at least an oxide or a nitride of the M and the X. The magnetic film has a saturation magnetic flux density of not less than 0.8 T and an electric resistivity of not less than 80 &mgr;&OHgr;cm.

Abstract: The present invention can provide a MgCuZn-based ferrite sintered compact which is constituted by having as substantial main component compositions 7.5 to 23.0 mole % of magnesium oxide, 7.0 to 20.0 mole % of copper oxide, 19.0 to 24.2 mole % of zinc oxide and 48.5 to 50.3 mole % of ferric oxide, and the average particle diameter of the ferrite sintered compact is in a range of 1.10 to 7.30 &mgr;m while the standard deviation &sgr; of the size distribution is in a range of 0.60 to 10.00, resulting in the ferrite sintered compact which has a high impedance with a frequency of not less than 50 MHz and is capable of efficiently cutting of radiant noise by selecting inexpensive materials.

Abstract: The invention aims to provide a manganese-zinc ferrite exhibiting a high initial permeability over a broad band and especially in a low-frequency region of about 10 kHz and a method for preparing the same. A method for preparing a manganese-zinc ferrite by firing is characterized in that the firing includes a main temperature holding step at 1,200-1,450° C. and a thermal ramp-down step prior to the main temperature holding step, and the lowest temperature reached by the mid-firing thermal ramp-down step is set in the range of 1,000-1,400° C. and lower by at least 50° C. than the hold temperature of the main holding step, thereby obtaining a manganese-zinc ferrite comprising 50-56 mol % calculated as Fe2O3 of iron oxide, 22-39 mol % calculated as MnO of manganese oxide, and 8-25 mol % calculated as ZnO of zinc oxide as main components, and having a mean crystal grain size of more than 50 &mgr;m to 150 &mgr;m.

Abstract: The present invention provides magnetostrictive composites that include an oxide ferrite and metallic binders which provides mechanical properties that make the magnetostrictive compositions effective for use as sensors and actuators.

Abstract: A method of producing a single crystal of the composition M3NbGa3Si2O14 (where M is an alkaline earth metal) comprising growing in a lattice direction inclined at an angle of 50.8 to 90 degrees from a [001] axis. The single crystal obtained in this way may be suitably used as a component of a resonator, filter, or other various piezoelectric elements.

Abstract: The invention aims to provide a manganese-zinc base ferrite having a high permeability over a broad band, especially in a frequency band near 10 kHz. The object is achieved by a manganese-zinc base ferrite which contains iron oxide, manganese oxide and zinc oxide as main components in amounts calculated as Fe2O3, MnO and ZnO, respectively, of 50-56 mol % Fe2O3, 21-27 mol % MnO, and 20-26 mol % ZnO, contains 0.0003-0.003% by weight calculated as P of phosphorus as an auxiliary component, and has a mean grain size from more than 50 &mgr;m to 200 &mgr;m.

Abstract: The present invention provides manganese-zinc-ferrite core fabrication process which can fabricate a manganese-zinc-ferrite core having high surface electrical resistance and low magnetic core losses without recourse to the introduction of nitrogen gas from the outside yet within a short time period, and such a manganese-zinc-ferrite core. To achieve this, manganese-zinc-ferrite core is formed into a given core shape. The core compact is fired in a firing atmosphere having an oxygen concentration controlled with carbonic acid gas and steam. Then, the compact is rapidly cooled at a cooling rate of 350° C./hour to 850° C./hour. In this way, a manganese-zinc-ferrite core is obtained.

Abstract: Ni—Cu—Zn based oxide magnetic materials, in that not only the internal conductor is stabilized at very low firing temperatures, but also the characteristics in the high frequency zones of 100 MHz or higher are excellent. The oxide magnetic materials composing, Fe2O3: 35.0 to 51.0 mol %, CuO: 1.0 to 35 mol %, NiO: 38.0 to 64.0 mol %, and ZnO: 0 to 10.0 mol % (including 0%).

Abstract: The present invention provides a Mn—Zn ferrite having an electrical resistivity exceeding 1 &OHgr;m order and having a high initial permeability of 3000 or more at 100 kHz and 100 or more at 10 MHz. The main components of the Mn—Zn ferrite are 44.0 to 49.8 mol % Fe2O3, 15.0 to 26.5 mol % ZnO, 0.02 to 1.00 mol % Mn2O3 and the remainder MnO. The Mn—Zn ferrite is enabled to be used in a wide frequency region from 100 kHz to 10 MHz by limiting Fe2O3 content to less than 50 mol % that is the stoichiometric composition and inhibiting formation of Mn2O3.

Abstract: A process for producing Mn—Zn ferrite is disclosed, which enables regeneration and reuse of scraps of a sintered product. The process comprises reusing a powder obtained by milling the sintered product of Mn—Zn ferrite, subjecting the powder to a component adjustment so as to have a composition of 44.0 to 50.0 mol % of Fe2O3, 4.0 to 26.5 mol % of ZnO, 0.1 to 8.0 mol % of at least one member selected from the group consisting of TiO2 and SnO2, and the remainder being MnO, and optionally 0.1 to 16.0 mol % of CuO, pressing the resulting mixed powder after the component adjustment, and then sintered a green compact.

Abstract: To use a media agitating mill of a wet internal circulation type when grinding materials, and offer oxide magnetic materials and coils in which influences of ZrO2 and Y2O3 mixing when using partially stabilized zirconia as media beads are improved. The magnetic materials and coils are characterized in that Fe2O3, ZnO, NiO and CuO are main components, and Y2O3, ZrO2 and Bi2O3 are contained with respect to these main components, where an amount of Y2O3 is 0.007 to 0.028 wt % for the total amount, an amount of ZrO2 is 0.12 to 0.55 wt % therefor and an amount of Bi2O3 is 0.03 to 10.12 wt % for the same.

Abstract: Magnetic ceramic compositions include a Fe compound, a Zn compound, a Ni compound and a Cu compound as primary components, and also includes a bismuth compound and a cobalt compound as additive components. The primary component composition ratio (Fe2O3, ZnO, NiO+CuO) represented by molar percent of Fe2O3, ZnO, and (NiO and CuO), is in the region enclosed by point A (48.0, 0.5, 51.5), point B (48.0, 1.5, 50.5), point C (45.5, 4.0, 50.5), point D (44.0, 4.0, 52.0), and point E (44.0, 0.5, 55.5) in a ternary diagram. About 8.0 to 14.0 molar percent of the Cu compound is included in 100 molar percent of the primary components as Fe2O3, ZnO, NiO, and CuO. About 0.25 to 1.0 part by weight of the bismuth compound as Bi2O3 and about 0.25 to 3.0 parts by weight of the cobalt compound as Co3O4 with respect to 100 parts by weight of the primary components are included.

Abstract: The present invention provides a Mn—Zn ferrite having an electrical resistivity exceeding 1 &OHgr;m order and having a high initial permeability of 4000 or more at 100 kHz and 100 or more at 10 MHz. The main components of the Mn—Zn ferrite include 44.0 to 49.8 mol % Fe2O3, 15.0 to 26.5 mol % ZnO, 0.1 to 3.0 mol % CoO, 0.02 to 1.00 mol % Mn2O3, and the remainder MnO. The Mn—Zn ferrite can be used in a wide frequency region of 100 kHz to 10 MHz by limiting Fe2O3 content to a range of less than 50 mol %, that is the stoichiometric composition, inhibiting formation of Mn2O3 and adding a proper amount of CoO.

Abstract: The Mn—Zn system ferrite according to the present invention contains main components comprising manganese oxide, zinc oxide and iron oxide, and subordinate components comprising bismuth oxide and molybdenum oxide. It comprises 22.0 to 25.0 mol % c of manganese oxide calculated as MnO, 22.0 to 25.0 mol% of zinc oxide calculated as ZnO and the remainder calculated as Fe2O3 in main components. It has been sintered after adding thereto 50 to 400 ppm of a bismuth oxide component calculated as Bi2O3 and 50 to 400 ppm of a molybdenum oxide component calculated as MoO3 as subordinate component source materials. An initial magnetic permeability at 10 KHz is 8,500 or more at −20 to 20° C. and 10,000 or more at 20 to 100° C., and the temperature characteristics of magnetic permeability is excellent.

Abstract: A Mn—Zn ferrite having large electrical resistance, which can withstand use in high frequency region exceeding 1 MHz, is provided. The Mn—Zn ferrite comprises the following basic components: 44.0 to 50.0 mol % Fe2O3, 4.0 to 26.5 mol % ZnO, 0.1 to 8.0 mol % at least one member selected from the group consisting of TiO2 and SnO2, and the remainder being MnO. By the addition of TiO2 and SnO2, even if the material is sintered in air, electrical resistance of 103 times that of the conventional Mn—Zn ferrite can be obtained, and high initial permeability of 300 to 400 as estimated can be secured even at high frequency of 5 MHz.

Abstract: Since the radio wave absorbent of the present invention has the main component of a magnesium-zinc system ferrite material containing 45 to 50 mol % of iron oxide, 7 to 19.7 mol % of magnesium oxide, 24 to 28.5 mol % of zinc oxide, 4 to 16 mol % of copper oxide, and 0.1 to 6 mol % of manganese oxide, a matching thickness is less than 8 mm, and the total weight of the radio wave absorbent for use in the inner wall of a radio wave dark room or the outer wall of a building or the like is remarkably reduced as compared with the radio wave absorbent obtained by sintering the conventional magnesium-zinc system ferrite material. Moreover, since the radio wave absorbent can be obtained by sintering the material at a relatively low sintering temperature of about 950 to 1150° C., the manufacture cost can be reduced relative to the radio wave absorbent obtained by sintering the conventional nickel-zinc system ferrite material.

Abstract: A magnetic ceramic composition containing ferrite serving as a primary component and a sintering aid. The composition can be sintered at low temperature. The sintering aid contains about 2-45 mol % Li2O; about 5-40 mol % RO, with R being at least one of Ba, Sr, Ca, and Mg; and about 30-70 mol % (Ti, Si)O2 with SiO2 accounting for at least about 15 mol %. The resultant composition provides inductor elements in which migration of inner conductors is suppressed, and insulation deterioration and increase of direct-current resistance is restrained.

Abstract: There is disclosed an MnMgCuZn ferrite material which contains ranges of 46.5 to 50.4 mol % of iron oxide, 10.5 to 22.0 mol % of magnesium oxide, 22.5 to 25.0 mol % of zinc oxide, 6.0 to 16.0 mol % of copper oxide, and 0.1 to 3.5 mol % of manganese oxide. Advantages of an MnMgCuZn ferrite material that resistivity is relatively high and material cost is low are utilized to realize a superior MnMgCuZn ferrite material which is much smaller in magnetic loss than conventional materials of the same series and which has a sufficient saturated magnetic flux density.

Abstract: Methods of preparing ferrite powders for use in microwave elements such as isolators, circulators, phase shifters and transmission line elements. In one method separate precipitations of metal dicarboxylate salts such as oxalates or malonates are mixed with a ferrous dicarboxylate. This is followed by mixing and calcining of the precipitated dicarboxylates to form the ferrite powder. In another method metal acetates in a solution of concentrated acetic acidare mixed with iron powder to form a solution which is mixed with malonic acid. The resulting mixed metal malonates are processed into a powder which is calcined to obtain the ferrite. To form a lithium ferrite, lithium carbonate is added to prepared powders prior to the calcining step.

Abstract: A method of producing a Ni—Cu—Zn ferrite material comprises the steps of preparing a mixture of an iron compound powder having a specific surface area of about 8.5 m2/g or more, a nickel compound powder, copper compound powder and a zinc compound powder, the mixture having a specific surface area of about 8.0 m2/g or more; pre-calcining the mixture such that the pre-calcined mixture has a surface area of about 5.0 m2/g or more and a spinel crystal synthesizability within a range of about 80.5% to 98%; and milling the pre-calcined mixture to obtain a powder of a Ni—Cu—Zn ferrite material having a specific surface area of about 6.0 m2/g or more.

Abstract: A ferrite oxide magnetic material containing, as basic composition, 11 to 19 mol % of iron oxide calculated in terms of Fe2O3, 11 to 25 mol % of zinc oxide calculated in terms of ZnO, 0 to 10 mol % of copper oxide calculated in terms of CuO, and a residual part of nickel oxide, and further containing, as components subsidiary to the basic composition, 0.01 to 15 wt % of lead oxide calculated in terms of PbO, and 0.01 to 15 wt % of silicon oxide and/or talc calculated in terms of SiO2, wherein the ferrite oxide magnetic material has an initial magnetic permeability of not higher than 8, a sintered density of not lower than 4.8 g/cm3 and a stress-resisting and magnetic-field-resisting characteristic in a range of ±5% calculated in terms of the rate &Dgr;L/L of the change of inductance due to the condition of a magnetic field of 1000 G under a compressive stress P=5 (kg/mm2) parallel with a direction of magnetization.

Abstract: A Mn—Zn ferrite having large electrical resistance, which can withstand the use in high frequency region exceeding 1 MHz, is provided. The Mn—Zn ferrite comprises the following basic components: 44.0 to 50.0 mol % Fe2O3, 4.0 to 26.5 mol % ZnO, 0.1 to 8.0 mol % at least one member selected from the group consisting of TiO2 and SnO2, 0.1 to 16.0 mol % CuO, and the remainder being MnO. By the addition of TiO2, SnO2 and CuO, even if the material is sintered in the air, electrical resistance of 103 times or more as high as that of the conventional Mn—Zn ferrite can be obtained, and a high initial permeability of 300-400 as estimated can be secured even at high frequency of 5 MHz.