High heat generation ability in AC magnetic field for nano-sized magnetic Y₃Fe₅O₁₂ powder prepared by bead milling

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• 作者：Hiromichi Aono^a ; ^{aono.hiromichi.mf@ehime-u.ac.jp} ; Hiroki Ebara^a ; Ryota Senba^a ; Takashi Naohara^a ; Tsunehiro Maehara^a ; Hideyuki Hirazawa^b ; Yuji Watanabe^c
• 关键词：Y3Fe5O12 ; Thermal coagulation therapy ; AC magnetic field ; Nano particle ; Bead milling
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2012
• 期刊代码：31_03048853
• 类别：ph
• 出版时间：June, 2012
• 卷：324
• 期：12
• 页码：1985-1991
• 文件大小：876 K

摘要

Nano-sized magnetic Y₃Fe₅O₁₂ ferrite having a high heat generation ability in an AC magnetic field was prepared by bead milling. A commercial powder sample (non-milled sample) of ca. 2.9 渭m in particle size did not show any temperature enhancement in the AC magnetic field. The heat generation ability in the AC magnetic field improved with a decrease in the average crystallite size for the bead-milled Y₃Fe₅O₁₂ ferrites. The highest heat ability in the AC magnetic field was for the fine Y₃Fe₅O₁₂ powder with a 15-nm crystallite size (the samples were milled for 4 h using 0.1 mm蠒 beads). The heat generation ability of the excessively milled Y₃Fe₅O₁₂ samples decreased. The main reason for the high heat generation property of the milled samples was ascribed to an increase in the N茅el relaxation of the superparamagnetic material. The heat generation ability was not influenced by the concentration of the ferrite powder. For the samples milled for 4 h using 0.1 mm蠒 beads, the heat generation ability (W g^鈭?) was estimated using a 3.58脳10^鈭? fH² frequency (f/kHz) and the magnetic field (H/kA m^鈭?), which is the highest reported value of superparamagnetic materials.