六方晶フェライトの軟磁性化と高機能化に関する研究

概要

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The substitution of elements was carried out to improve the soft magnetic properties in hexagonal ferrites. A series of Ba3Co2RxFe24-xO41 samples (R=La, Nd, Gd, Dy, Ho, Yb) with Z-type structure were made. The initial permeability of Gd3+-substituted sample (x=0.1) was the highest of all samples, because the apparent specific anisotropy field of the sample was the lowest. The substituted sample Ba3Co2Mn0.5xTi0.5xFe24-xO41 with x=0.4 had the maximum μ of 25.7 and μ × fr product of 17.6 GHz. The M-T curve showed an anomalous drop below the Curie temperature, which reflected the change from in-plane magnetic anisotropy to vertical one with increasing temperature. BaCoxTixFe12-2xO19 (x=1-3) were prepared. The initial permeability increased to 27 for a sample with x=1.15. The reason for this may be that the coercivity becomes small as a result of the decrease in the anisotropic magnetic field. SrCo2+yMe4+yFe12-2yO19 (Me=Zr, Hf) samples were also fabricated. For SrCoyZryFe12-2yO19 (y=0-1.2), magnetization increased slightly for the sample of y=0.4, and then decreased with increasing y. Coercivity drastically decreased up to y=1.2. Magnetic behavior of the Co-Hf substituted sample was similar to that of the Co-Zr substituted one.
2010-12-15