Patent ID: 7470498

Claim:
A Mg-based ferrite material consisting essentially of MgO and Fe 2 O 3 components or of CaO, MgO and Fe 2 O 3 components, and having a composition of formula (1) Ca a Mg b Fe c O d (1), wherein a, b, and c satisfy 0.10 ≦b/ ( b+c/ 2) ≦0.85 and 0 ≦ R (Ca) ≦0.10, wherein R(Ca) is expressed as R(Ca) = a×Fw (CaO)/( a×Fw (CaO)+ b×Fw (MgO) +( c/ 2) ×Fw (Fe 2 O 3 )) (Fw(A): formula weight of A); and d is determined by oxidation numbers of Ca, Mg and Fe; wherein said Mg-based ferrite material has a saturation magnetization measured at 14 kOe using an vibrating sample magnetometer, in the range of 30-80 emu/g, wherein said Mg-based ferrite material has a dielectric breakdown voltage in the range of 1.0-5.0 kV.