Abstract Dendritic nanostructures of fluorinated α-Fe 2 O 3 are synthesized using Potassium Ferrocyanide along with Selectfluor™ (F-TEDA), HF, TBABF 4 , NaF and NH 4 F as Fe and F precursors respectively in an in-situ hydrothermal process. The choice of sources is based on the nature of fluorine; F-TEDA uniquely acts as a source for electrophilic fluorine while others are nucleophilic in nature. The effect of fluorination on α-Fe 2 O 3 nanostructures is examined from the interplay between (110) and (104) growth direction and crystallite size by X-Ray diffraction analysis and the amount of fluorination is observed by elemental analysis. A significant change in the magnetic property of α-Fe 2 O 3 is observed for different concentrations of F-TEDA. Pristine α-Fe 2 O 3 undergoes an antiferromagnetic to ferromagnetic transition with saturation magnetization value of ~ 13 emu/g and coercivity of 109.8 Oe. However, α-Fe 2 O 3 nanostructures prepared with HF, NH 4 F, TBABF 4 and NaF in absence of fluorination remain antiferromagnetic despite of changes in preferred orientation and crystallite size. The interesting magnetic properties arising from F-TEDA is attributed to surface fluorination that results in uncompensated surface spins.

中文翻译：

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α-Fe 2 O 3 纳米结构的亲电氟化及其对磁性能的影响

摘要 氟化 α-Fe 2 O 3 的树枝状纳米结构分别使用亚铁氰化钾和 Selectfluor™ (F-TEDA)、HF、TBABF 4 、NaF 和 NH 4 F 作为 Fe 和 F 前体在原位水热过程中合成。来源的选择基于氟的性质；F-TEDA 独特地充当亲电氟的来源，而其他的则是亲核的。通过X射线衍射分析从(110)和(104)生长方向和微晶尺寸之间的相互作用来检查氟化对α-Fe 2 O 3 纳米结构的影响，并且通过元素分析观察氟化量。对于不同浓度的 F-TEDA，观察到 α-Fe 2 O 3 的磁性能发生显着变化。原始的 α-Fe 2 O 3 经历了反铁磁到铁磁的转变，饱和磁化强度值为 ~ 13 emu/g，矫顽力为 109.8 Oe。然而，尽管优选取向和微晶尺寸发生变化，但在没有氟化的情况下，用 HF、NH 4 F、TBABF 4 和 NaF 制备的 α-Fe 2 O 3 纳米结构仍保持反铁磁性。F-TEDA 产生的有趣磁性归因于表面氟化，导致未补偿的表面自旋。