| Autor: |
Hongchao Yang, Xiaobo Mao, Yanjun Guo, Dongwei Wang, Guanglu Ge, Rong Yang, Xiaohui Qiu, Yanlian Yang, Chen Wang, Yinshu Wang, Gang Liu |
| Předmět: |
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| Zdroj: |
CrystEngComm; Jun2010, Vol. 12 Issue 6, p1842-1849, 8p |
| Abstrakt: |
Porous hematite (α-Fe2O3) with branched nanostructures such as V and Y shapes were prepared through dehydration of goethite (α-FeOOH) precursor, while α-FeOOH branched nanostructures are self-organized by straight nanorods viafacet-mediated oriented attachment mechanism at high pH without the use of organic additives. This novel approach is different from the mechanisms reported for other α-Fe2O3anisotropic structures. Based on combined TEM, high-resolution TEM and AFM analyses, a possible formation mechanism of branched nanostructures was suggested. A V-shaped rod with a dihedral angle of (118.0 ± 4.0)° is connected by two straight needle-shaped rods sharing comparable three dimensions; the subsequent merger of a V-shaped rod with a straight rod leads to a Y-shaped rod. This is the first demonstration of branched topology with single-domain crystallinity for α-Fe2O3. The as-prepared α-Fe2O3nanostructures displays two Morin transition temperatures at 195 and 243 K. The results from the current study could provide potential implications in self- and directed-engineering shape anisotropy with unique and useful magnetic and other properties through the oriented attachment mechanism. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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