CTAB-assisted low-temperature synthesis of SrFe₁₂O₁₉ ultrathin hexagonal platelets and its formation mechanism

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• 作者：D.Y. Chen ; Y.Y. Meng ; D.C. Zeng ; ^{medczeng@scut.edu.cn} ; Z.W. Liu ; H.Y. Yu ; X.C. Zhong
• 关键词：Magnetic materials ; Microstructure ; Strontium ferrite ; CTAB
• 刊名：Materials Letters
• 出版年：2012
• 期刊代码：59_0167577x
• 类别：ms
• 出版时间：1 June, 2012
• 卷：76
• 期：Complete
• 页码：84-86
• 文件大小：616 K

摘要

Single domain particles (50-150 nm) of the M-type strontium ferrite (SrFe₁₂O₁₉) were synthesized via co-precipitation method using cetyltrimethyl ammonium bromide (CTAB) as a surfactant, followed by heat treatment at 900 掳C for 2 h. The effects of CTAB contents (x = 0, 1, 3, 6, 9 wt.%) on formation, structure, morphology and magnetic properties of the strontium hexaferrite particles were investigated. Single phase M-type ferrite powders with ultrathin hexagonal platelet-like (thickness: 10-20 nm) morphology were obtained in the existence of CTAB surfactant, whereas secondary phase 伪-Fe₂O₃ was detected in the samples prepared without CTAB, exhibiting rod-like shape. Both the saturation magnetization and coercivity increased with CTAB content up to x = 6 wt.%and the optimal values were 68.7 emu/g and 6620 Oe, respectively. These results implied that CTAB may act as a crystallization master, controlling the nucleation and growth of the crystals. Two distinct formation mechanisms have been proposed to explain the different SrFe₁₂O₁₉ particle morphologies. These nanoparticles are promising for the building blocks of hard magnets and magnetic recordings.