采用并加共沉淀工艺在900℃热处理2h的条件下合成了单相钡过量非化学计量M型铁氧体Ba1+xCoTiFe10O19+x(x=0.00、0.05、0.10、0.15、0.20), 并用XRD、SEM、TEM和VSM表征了这种新的非化学计量M型铁氧体的结构和磁学特性. 结果表明: 当0<x≤0.05时, 矫顽力Hc和剩余磁化强度σr均随x增大而显著增大(Δσr=5.36A·m2·kg-1, ΔHc=16.99 kA·m-1, 但比饱和磁化强度σs基本不变; 0.05<x≤0.20时, 因为Fe3+离子被稀释导致σs、Hc和σr均随x增大而持续降低. 同时证实钡过量并不会导致晶体对称性破坏, 0<x≤0.10时a轴长明显增大而c轴长增量很小, 0.1<x≤0.20时c轴长大幅度增大而a轴长几乎无变化. 此外, 还发现钡过量可导致晶粒长大和晶形由平面型向单轴型转变. 这些结果说明过量Ba2+离子分布于平行于a轴方向的大孔隙位?置, 不仅具有助熔剂作用, 而且对磁畴壁产生了钉扎效应.
Single-phase non-stoichiometric M-type hexaferrite with a certain barium surplus Ba1+xCoTiFe10O19+x
(x=0.00, 0.05, 0.10, 0.15, 0.20) was synthesized by calcining the precursors at 900℃ for 2h obtained with the co-dump coprecipitation
process. Structural and magnetic properties of the new non-stoichiometric M-type hexaferrite were investigated with XRD,
SEM, TEM, VSM. The results show that the coercive field (Hc) and the remanent magnetization (σr) of Ba1+xCoTiFe10O19+x are significantly increased
(Δ Hc=16.99kA·m-1, Δσr=5.36A·m2·kg-1) while the specific saturation magnetization (σs) keep almost constant as the x increases in the range 0～0.05, and that
σs, Hc and σr all continuously decrease as the x increases in the range 0.05～0.20 since Fe3+ ions become diluted. At the same time, it is confirmed that the crystal symmetry of
Ba1+xCoTiFe10O19+x is not destroyed in the x range 0～0.20; the a-axis length is significantly increased as the x increase in the
range 0～0.10 accompanying a small increase of the c-axis length, and that the a-axis length almost not change although the c-axis length stably
increases as the x farther increases in the range 0.10～0.20. In addition, the phenomena of the growth of crystal grains and crystal shape
transformation from plane form to uniaxial one were observed by a series of SEM and TEM images. These results imply that the excessive barium cations,
which not only act as fluxing agent but also produce the pinning effect to magnetic domainwall, are distributed in large holes along a-axis
orientation of M-type barium hexaferrite.
参考文献
| [1] | 张永祥, 耿香月, 李玲霞, 等. 天津大学学报, 1999, 32 (5): 611--615. [2] Sugimoto S, Kondo S, Okayama K, et al. IEEE Transactions on Magnetics, 1999, 35 (5): 3154--3156. [3] Cho H S, Kim S S. IEEE Transactions on Magnetics, 1999, 35 (5): 3151--3153. [4] 邓龙江, 谢建良, 梁迪飞, 等. 功能材料, 1999, 30 (2): 118--121. [5] Mitsuo S. Journal of America Ceramic Society, 1999, 82 (2): 269--280. [6] Nedkov H, Petkov A, Karpov V. IEEE Transactions on Magnetics, 1990, 26 (5): 1483--1484. [7] Sugimoto S, Okayama K, Kondo S, et al. Materials Transactions JIM, 1998, 39 (10): 1080--1083. [8] Vincent H, Brando E, Sugg B. Journal of Solid State Chemistry, 1995, 120: 17--22. [9] Rane M V, Bahadur D, Nigam A K, et al. Journal of Magnetism and Magnetic Materials, 1999, 192: 288--296. [10] Bai Y, Zhou J, Gui Z L, et al. Journal of Magnetism and Magnetic Materials, 2002, 250: 364--369. [11] 赵文俞, 官建国, 张清杰. 功能材料, 2004, 35 (1): 25--27. [12] 赵文俞, 张清杰, 李鹏, 等(ZHAO Wen-Yu, et al). 硅酸盐学报(Journal of the Chinese Ceramic Society), 2003, 31 (1): 20--24. |
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