Ordered mesoporous Fe2O3 with crystalline walls
Ordered mesoporous Fe2O3 with crystalline walls
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DOI：
10.1021/ja0584774
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发表时间：
2006-04-26
影响因子：
15
通讯作者：
Bruce, PG
中科院分区：
文献类型：
--
作者：
Jiao, F;Harrison, A;Bruce, PG
α-Fe 2 O3已被合成为具有有序的中孔结构和显示出近单晶状有序的结晶壁。该材料的独特的磁性行为，不同于散装纳米粒子的α-Fe 2 O3或介孔Fe 2 O3与无序壁，已被建立。磁化率，穆斯堡尔谱，和中子衍射数据表明，该材料具有相同的长程磁秩序散装α-Fe 2 O3，尽管壁厚小于8 nm的限制，低于该磁秩序打破nanciparticulate α-Fe 2 O3，但桑色素过渡散装α-Fe 2 O3是不存在的。TEM、PXRD和EXAFS还表明，具有相同有序介孔结构但壁无序的α-Fe 2 O3含有小的晶畴。穆斯堡尔谱和磁化率数据表明，这种材料没有长程磁序，但超顺磁性行为。
alpha-Fe2O3 has been synthesized with an ordered mesoporous structure and crystalline walls that exhibit a near-single crystal-like order. The unique magnetic behavior of the material, distinct from bulk nanoparticles of alpha-Fe2O3 or mesoporous Fe2O3 with disordered walls, has been established. Magnetic susceptibility, Mossbauer, and neutron diffraction data show that the material possesses the same long-range magnetic order as bulk alpha-Fe2O3, despite the wall thickness being less than the 8 nm limit below which magnetic ordering breaks down in nanciparticulate alpha-Fe2O3, yet the Morin transition of bulk alpha-Fe2O3 is absent. It is also shown by TEM, PXRD, and EXAFS that alpha-Fe2O3 with the same ordered mesoporous structure but disordered walls contains small crystalline domains. Mossbauer and magnetic susceptibility data demonstrate that this material exhibits no long-range magnetic order but superparamagnetic behavior.