Patent ID: 7524433

Claim:
A ferrite material formed of a sintered body comprising, as main constituents, Fe 2 O 3 : 47.0 to 50.0 mol %, CuO: 1 to 5 mol %, NiO: 20 to 26 mol %, and ZnO substantially constituting the balance and its upper limit being less than 25.4 mol %, wherein said sintered body comprises: 40 ppm or less of P in terms of P 2 O 5 and 50 to 1500 ppm of one or more additives of Al 2 O 3 and MgO in relation to the sum of the contents of said main constituents, and the initial permeability μi (at 100 kHz) is 320 or more; the absolute value of aμir −40 to 20 is 13 ppm/° C. or less the absolute value of aμir 20 to 100 is 22 ppm/° C. or less and the saturation magnetic flux density Bs (applied magnetic field: 4000 Nm) is 470 mT or more, where αμ ir −40 to 20 =[(μ i 20 −μi −40 )/μ i 20 2 ]×[1 /T 20 −T −40 )], αμ ir 20 to 100 =[(μ i 100 −μi 20 )/ μi 20 2 ]×[1 /T 100 −T 20 )], μi −40 : the initial permeability at −40° C., μi 20 : the initial permeability at 20° C., and μi 100 : the initial permeability at 100° C., wherein the mean grain size of the sintered body is 12 μm or less and the standard deviation of the grain size thereof is 4.5 μm or less, wherein said sintered body density is 5.27 Mg/m 3 or more.