Flaky magnetic metal particles of embodiments each have a flat surface and a magnetic metal phase containing iron (Fe), cobalt (Co), and silicon (Si). An amount of Co is from 0.001 at % to 80 at % with respect to the total amount of Fe and Co. An amount of Si is from 0.001 at % to 30 at % with respect to the total amount of the magnetic metal phase. The flaky magnetic metal particles have an average thickness of from 10 nm to 100 μm. An average value of the ratio of the average length in the flat surface with respect to a thickness in each of the flaky magnetic metal particles is from 5 to 10,000. The flaky magnetic metal particles have the difference in coercivity on the basis of direction within the flat surface.

An embodiment provides a magnetic core comprising a first powder and a second powder, wherein the hardness of the first powder is lower than that of the second powder, and the volume of the first powder is 40% to 60% with respect to the combined volume of the first powder and the second powder.

The present invention relates to an electromagnetic shielding sheet capable of improving reliability. Particularly, the present invention provides a composite magnetic sheet for electromagnetic shielding structured such that an independent soft magnetic sheet, which has a low surface roughness, is laminated on the outermost surface of a soft magnetic sheet having a lamination structure, thereby implementing laminated composite sheets having different surface roughness or porosity characteristics; as a result, the reliability in an external hazardous environment, such as saline water, can be substantially enhanced while maintaining the efficiency of electromagnetic shielding.

Provided are a new, highly magnetically stable magnetic material which has higher saturation magnetization than ferrite-based magnetic materials, and with which problems of eddy current loss and the like can be solved due to higher electric resistivity than that of existing metal-based magnetic materials, and a method for manufacturing the same. A magnetic material powder is obtained by reducing in hydrogen Ni-ferrite nanoparticies obtained by wet synthesis and causing grain growth, while simultaneously causing nanodispersion of an α-(Fe, Ni) phase and an Ni-enriched phase by means of a phase dissociation phenomenon due to disproportional reaction. The powder is sintered to obtain a solid magnetic material.

Provided are: a novel magnetic material having high magnetic stability, in particular, having an extremely high saturation magnetization; and a method for producing the same, wherein the magnetic material, due to having a higher saturation magnetization than ferrite magnetic materials and a higher electrical resistivity than existing metallic magnetic materials, resolves problems such as eddy current loss. According to the present invention, Co-ferrite nanoparticles obtained by wet synthesis are reduced in hydrogen and subjected to grain growth, and bcc- or fcc-(Fe, Co) phases and Co-enriched phases are nano-dispersed using phase separation via a disproportionation reaction to prepare a magnetic material powder. In addition, the magnetic material powder is sintered into a solid magnetic material.

A wireless device having electromagnetic shielding for a coil includes a composite magnetic sheet. The composite magnetic sheet includes first and second magnetic sheet parts. The first magnetic sheet part has a stacked structure of magnetic sheets including a surface which is an outermost surface of the first magnetic sheet part. The second magnetic sheet part is disposed on the outermost surface of the first magnetic sheet part. At least one magnetic sheet of the first magnetic sheet part includes a cracked structure and the second magnetic sheet part does not include a cracked structure. A protective member is disposed above the composite magnetic sheet. A coil is disposed below the composite magnetic sheet. A magnetic sheet of the first magnetic sheet part with a cracked structure has a surface roughness or porosity greater than that of the second magnetic sheet part without a cracked structure.

A soft magnetic powder, including an Fe alloy, and containing 0.1 to 15 mass % of Si, wherein a ratio (Si/Fe) of an atomic concentration of Si and an atomic concentration of Fe is from 4.5 to 30 at a depth of 1 nm from a particle surface of the soft magnetic powder.

A magnetic material according to an embodiment includes at least one first element X selected from the group consisting of Fe, Co and Ni; a matrix phase; and a particle including C and at least one second element Y selected from Ta, W, Nb and Mo.

Flaky magnetic metal particles of embodiments each have a flat surface and a magnetic metal phase containing iron (Fe), cobalt (Co), and silicon (Si). An amount of Co is from 0.001 at% to 80 at% with respect to the total amount of Fe and Co. An amount of Si is from 0.001 at% to 30 at% with respect to the total amount of the magnetic metal phase. The flaky magnetic metal particles have an average thickness of from 10 nm to 100 .Math.m. An average value of the ratio of the average length in the flat surface with respect to a thickness in each of the flaky magnetic metal particles is from 5 to 10,000. The flaky magnetic metal particles have the difference in coercivity on the basis of direction within the flat surface.

A soft magnetic powder according to the present disclosure comprises a particle having no hollow part as a main component, wherein a number of hollow particle present in a region of 2.5 mm square is 40 or less in a cross section of a molded body obtained by powder-compacting and molding the soft magnetic powder so as to have a volume filling rate of 75% or more and 77% or less (i.e., from 75% to 77%).