Effect of Co-doping on magnetic properties of Bi₃Fe₅O₁₂ garnet films

抄録

  Co-doped Bi₃Fe₅O₁₂ garnet films were prepared using two targets (T_A = 3Bi₂O₃-5Fe₂O₃ and T_B = CoFe₂O₄ or Co metal) by means of reactive alternating ion beam sputtering technique. Co spinel ferrite phase was also observed by X ray diffraction measurement (XRD), even when garnet phase mainly grows. The saturation magnetization showed a peak for the sputtering time ratio R. The coercive force of the films monotonously increased with decrease of R. The films also showed irregular Faraday rotation and magnetization hysteresis loops. The films deposited using CoFe₂O₄ as Co source formed G phase in the wider range than those deposited using Co metal of CoO. From these phenomena, it turned out that Co ion exists as Co spinel ferrite particles scattered in Bi₃Fe₅O₁₂ films independent of Co source materials.