| In this thesis, several magnetic oxide nanostructures, including fractalα-Fe2O3 dendrites, Fe3O4 nanowires, MnFe2O4 nanorods and MFe2O4 (M=Ni, Co, Zn) nanoparticles were synthesized via hydrothermal techniques. The morphpolgy control was achieved by manipulating experiment parameters and introducing surfactants. The composition, morphologies and structures of the prepared samples were investigated by X-ray diffraction (XRD), M?ssbauer spectrum, scanning electron microscope (SEM), transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM). The magnetic properties were measured by vibrating sample magnetometer (VSM). The possible growth mechanism for the nanostructures was also discussed.The fractal single-crystallineα-Fe2O3 dendrites were synthesized via a simple hydrothermal route. The morphology was controllably transferred into a micro-snowflake shap with the assistance of surfactant NP-9. Both the micro-plines and micro-snowflakes lie on the (0001) crystal plane and grow along the < 112 0> directions.The Fe3O4 nanowires with a uniform morphology were high-yieldly prepared via a hydrothermal route with the assistance of surfactant PEG. As-prepared nanowires were 15 nm in diameter and 2~3μm in length. Fe3O4 nanowires are single-crystalline, and the growth direction is along <100> axis. Compared with nanoparticles, the Fe3O4 nanowires have much higher magnetic anisotropy, with a saturation magnetization of 23.0 emu/g. Large scale MnFe2O4 nanorods with a uniform morphology were synthesized via the hydrothermal method. As-prepared nanorods are single-crystalline, 20 nm in diameter and 500 nm in length, and grow along <111> axis. The nanorods have excellent magnetic properties, of which the saturation magnetization is 74.0 emu/g, very close to the value of the corresponding bulk materials.Uniform MFe2O4 (M=Ni, Co, Zn) nanoparticles were prepared hydrothermally with a large scale and high yield by exchanging the metal cations.
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