Structural and Magnetic Properties of Monophasic Maghemite (<i>γ</i>-Fe<sub>2</sub>O<sub>3</sub>) Nanocrystalline Powder
Structural and Magnetic Properties of Monophasic Maghemite (<i>γ</i>-Fe<sub>2</sub>O<sub>3</sub>) Nanocrystalline Powder作者机构：Cavendish Laboratory Department of Physics University of Cambridge Cambridge UK Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional Cinvestav Unidad Saltillo Ciudad de México México Ciudad de México México Laboratorio de Cerámicos y Nanomateriales Facultad de Ciencias Físicas Universidad Nacional Mayor de San Marcos Lima Perú Laboratorio de Nanotecnología e Innovación Tecnológica Departamento de Química e Ingeniería Química Universidad Nacional Mayor de San Marcos Lima Perú Núcleo de Física Aplicada Instituto de Física Universidade de Brasília Brasília Brasil
出 版 物：《Advances in Nanoparticles》 (纳米粒子（英文）)
年 卷 期：2014年第3卷第3期
页 面：114-121页
主 题：Monophasic Nanomaghemite Rietveld Refinement TEM SAED M-H Loops ZFC
摘 要：Structural and magnetic studies of monophasic maghemite (γ-Fe2O3) magnetic nanocrystallites (MNCs) synthesized by the co-precipitation chemical route are reported in this paper. For the synthesis, a starting precursor of magnetite (Fe3O4) in basic medium was oxidized at room temperature by adjusting the pH = 3.5 at 80°C in an acidic medium without surfactants. X-ray diffraction (XRD) pattern shows widened peaks indicating nanometric size and Rietveld Refinement confirms only one single-phase assigned to γ-Fe2O3 MNCs. High Resolution Transmission Electron Microscopy (HR-TEM) demonstrates the formation of nanoparticles with diameter around D ≈ 6.8 ± 0.1 nm which is in good agreement with Rietveld Refinement (6.4 ± 1 nm). A selected area electron diffraction pattern was carried out to complement the study of the crystalline structure of the γ-Fe2O3 MNCs. M(H) measurements taken at different temperatures show almost zero coercivity and remanence indicating superparamagnetic domain and high magnetic saturation.
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