Structural and Magnetic Properties of Monophasic Maghemite (<i>γ</i>-Fe₂O₃) Nanocrystalline Powder  

作　　者：Juan Adrián Ramos Guivar Arturo Isaías Martínez Ana Osorio Anaya Luis De Los Santos Valladares Lizbet León Félix Angel Bustamante Dominguez 

机构地区：[1]Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK [2]Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Cinvestav, Unidad Saltillo, Ciudad de México, México Ciudad de México, México [3]Laboratorio de Cerámicos y Nanomateriales, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Lima, Perú [4]Laboratorio de Nanotecnología e Innovación Tecnológica, Departamento de Química e Ingeniería Química, Universidad Nacional Mayor de San Marcos, Lima, Perú [5]Núcleo de Física Aplicada, Instituto de Física, Universidade de Brasília, Brasília, Brasil

出　　处：《Advances in Nanoparticles》2014年第3期114-121,共8页纳米粒子（英文）

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.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.

关 键 词：MONOPHASIC Nanomaghemite RIETVELD Refinement TEM SAED M-H Loops ZFC 

分 类 号：O6[理学—化学]