Controlled synthesis and magnetic properties of Fe_3O_4 walnut spherical particles and octahedral microcrystals  

作　　者：JIAO Hua1,2 & YANG HeQing1 1 Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Materials Science, Shaanxi Normal University, Xi’an 710062, China 2 Department of Chemistry and Chemical Engineering, Weinan Teachers University, Wei nan 714000, China 

出　　处：《Science China(Technological Sciences)》2008年第11期1911-1920,共10页中国科学（技术科学英文版）

基　　金：Fund of weinan Teachers University (Grant No. 08YKZ008);the National Natural Science Foundation of China (Grant No. 20573072) ; Doctoral Fund of Ministry of Education of China (Grant No. 20060718010)

摘　　要：Magnetite Fe3O4 walnut spherical particles and octahedral microcrystals were suc- cessfully synthesized from K4 [Fe (CN) 6], K3 [Fe (CN) 6] and NaOH reagents via a simple hydrothermal process. And the uniform morphology of octahedral micro- crystals was obtained in the presence of ethylene glycol. The morphology and structure of products were characterized by powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results showed that the Fe3O4 walnut spherical particles and octahedral microcrystals were single crystals with the face-center cubic structure and with size distributions from 2.2 to 8.6 μm and 1.6 to 12.5 μm, respectively. Their magnetic properties were detected by a vibrating sample magnetometer at room temperature. The walnut spherical parti- cles exhibited a ferromagnetic behavior with the coercive force (Hc), saturation magnetization (Ms) and remanent magnetization (Mr) being 150.57 Oe, 97.634 and 12.05 emu/g, respectively. For the octahedral microcrystals they were 75.28 Oe, 101.90 and 6.69 emu/g, respectively. Different sizes of walnut spherical particles were controlled synthesized through adjusting the NaOH concentration. It was found that ethylene glycol molecules have a significant effect on the formation of Fe3O4 octahedra. A possible mechanism was also proposed to account for the growth of these Fe3O4 products

关 键 词：a HYDROTHERMAL route FE3O4 WALNUT spherical particles OCTAHEDRAL MICROCRYSTALS MAGNETIC property 

分 类 号：TM27[一般工业技术—材料科学与工程]