Synthesis and Magnetic Investigation of Ordered Mesoporous Two-Line Ferrihydrite

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• 作者：Harun T&uuml ; ys&uuml ; z ; Elena Lorena Salaba ; Claudia Weidenthaler ; Ferdi Sch&uuml ; th
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：January 9, 2008
• 年：2008
• 卷：130
• 期：1
• 页码：280 - 287
• 全文大小：472K
• 年卷期：v.130,no.1(January 9, 2008)
• ISSN：1520-5126

文摘

We report here for the first time on the synthesis and characterization of ordered mesoporoustwo-line ferrihydrite. Ordered mesoporous ferrihydrite has been prepared via the nanocasting route. Twotypes of ordered mesoporous silica, two-dimensional hexagonal SBA-15 and three-dimensional cubic KIT-6, were employed as hard templates. The magnetic behavior of ferrihydrite replicas with an average diameterof about 7 nm was investigated by direct current magnetometry. The temperature dependence ofmagnetization shows a superparamagnetic transition around 70 K. Field-induced changes in the low-fieldbehavior of the magnetization were observed below 30 K. The results are explained assuming a spin-glass-like state of the surface spins. The 2D hexagonal two-line ferrihydrite showed very large coercivityup to 1.6 kOe at 5 K.