Patent ID: 7289010

Claim:
A Mn—Zn based ferrite member comprising: a magnetic body formed of a Mn—Zn based ferrite sintered body; and a surface layer portion formed on the surface area of said magnetic body and having the properties that ρ5 defined below satisfies the relation that ρ5≧10 3 Ωm and ρ50 defined below satisfies the relation that ρ50≦10 2 Ωm, with the proviso that ρ5: (R0−R1)S/L5 (ρm) and ρ50: (R2−R3)S/L50 (Ωm), wherein: L5=10 μm; L50 20 μm; R0 (Ω) represents a resistance value between an electrode formed on the whole area of a first surface of a measurement sample A and an electrode formed on the whole area of a second surface thereof, the measurement sample A being taken from said Mn—Zn based ferrite member, having said first surface and said second surface that are parallel and opposed to each other, and forming a columnar body of a constant sectional area S (mm 2 ) between said first surface and said second surface, with said first surface being an outside exposed surface of said Mn—Zn based ferrite member and said second surface being a surface separated by 100 μm or more from the outside exposed surface in said Mn—Zn based ferrite member); R1 (Ω) represents a resistance value between an electrode formed on the whole area of a polished surface formed by polishing away a 10 μm layer from said first surface of said measurement sample A and said electrode formed on the whole area of said second surface; R2 (Ω) represents a resistance value between an electrode formed on the whole area of a polished surface formed by polishing away a 40 μm layer from said first surface of said measurement sample A and said electrode formed on the whole area of said second surface; and R3 (Ω) represents a resistance value between an electrode formed on the whole area of a polished surface formed by polishing away a 60 μm layer from said first surface of said measurement sample A and said electrode formed on the whole area of said second surface.