Patent ID: 7195717

Claim:
The A ferrite core for RFID application comprising a sintered oxide containing at least 48.6 to 53.9 mol % of Fe on Fe 2 O 3 basis, 12.3 to 35.2 mol % of Ni on NiO basis and 16.4 to 37.0 mol % of Zn on ZnO basis as metal elements, and contains a crystal phase comprising two or more kinds of solid solutions selected from NiFe 2 O 4 , ZnFe 2 O 4 and FeFe 2 O 4 , wherein full width at half maximum of a diffraction peak, of said crystal phase of which diffraction angle 2θ is in a range from 34.6 to 36.4° as measured by X-ray diffraction analysis using Cu—Kα beam, is 0.4 or less, wherein 9 parts by weight or less of Cu on CuO basis is contained for 100 parts by weight of said sintered oxide, wherein 0.001 to 0.6 parts by weight of Zr on ZrO 2 basis is contained for 100 parts by weight of said sintered oxide, Zr is uniformly distributed in said sintered oxide and thickness of the grain boundary phase in said sintered oxide is 20 nm or less.