Patent ID: 8404142

Claim:
A MnZn ferrite comprising: a basic component consisting essentially of ferrite oxide (in terms of Fe 2 O 3 ): 51.0 to 54.5 mol %, zinc oxide (in terms of ZnO): 8.0 to 11.0 mol %, and manganese oxide (in terms of MnO): balance; a sub component consisting of silicon oxide (in terms of SiO 2 ): 50 to 400 mass ppm, and calcium oxide (in terms of CaO): 50 to 4000 mass ppm; and unavoidable impurities comprising: phosphorous: less than 3 mass ppm, boron: less than 3 mass ppm, sulfur: less than 5 mass ppm, and chlorine: present but in an amount less than 10 mass ppm, wherein the sub component is added to the basic component, the ferrite has an incremental permeability μΔ value of 250 or more in a temperature range of 0 to 85° C. and 400 or more at a temperature of 65° C. when an 80 A/m direct current magnetic field is applied and the ferrite has an average crystal grain size of 5 to less than 15 μm.