| US 7,540,972 B2 | ||
| Mn-Zn based ferrite material | ||
| Tomokazu Ishikura, Tokyo (Japan); Shinichi Sakano, Tokyo (Japan); and Masahiko Watanabe, Tokyo (Japan) | ||
| Assigned to TDK Corporation, Tokyo (Japan) | ||
| Filed on Jan. 23, 2007, as Appl. No. 11/625,853. | ||
| Claims priority of application No. 2006-093716 (JP), filed on Mar. 30, 2006. | ||
| Prior Publication US 2007/0228319 A1, Oct. 04, 2007 | ||
| Int. Cl. H01F 1/34 (2006.01) | ||
| U.S. Cl. 252—62.62 [252/62.59; 252/62.63] | 11 Claims |
| 1. A Mn—Zn based ferrite material comprising:
as main constituents,
Fe2O3: 53 to 56 mol %;
ZnO: 7 mol % or less (inclusive of 0 mol %); and
the balance: MnO; and
as additives,
Co: 0.15 to 0.65 % by weight in terms of Co3O4;
Si: 0.01 to 0.045 % by weight in terms of SiO2; and
Ca: 0.05 to 0.40 % by weight in terms of CaCO3;
wherein:
the δ value (the cation defect amount) in the following ferrite composition formula (1) satisfies the relation 3.5×10−3<δ≤7×10−3; and
the mean grain size is larger than 8 μm and 15 μm or less;
the composition formula (1) being represented as follows:
(Zna2+, Mnc2+, Mnd3+, Fee2+, Fef3+, Cog2+, Coh3+)3O4+δ Formula (1)
wherein a+c+d+e+f+g+h=3, and δ=a +c+(3/2)d+e+(3/2)f+g+(3/2)h−4 with the proviso that g:h=1:2.
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