Patent ID: 6940381

Claim:
A Mn—Zn based ferrite having a main component comprised of 51 to 54 mol % of an iron oxide in Fe 2 O 3 conversion, 14 to 21 mol % of a zinc oxide in ZnO conversion and the rest of a manganese oxide, wherein a content (α [ppm]) of cobalt oxide in a CoO conversion with respect to 100 wt % of said main component satisfies a relation formula below: Relation formula: Y1≦α≦Y2 (1) wherein Y1 and Y2 are expressed by the formulas below and CoO>0 [ppm]: Y 1=(−0.13 ·B 2 +1.5 ·B −15.6 A +850)/(0.0003 ·B +0.0098)−233 (2) Y 2=(−0.40 ·B 2 +4.6 ·B −46.7 A +2546)/(0.0003 ·B +0.0098)+1074 (3) wherein the A and B in the above Y1 and Y2 are A=Fe 2 O 3 (mol %) and B=ZnO (mol %).