Co_xZn_(1-x)Fe_2O_4 (0.5 <=x<= 1.0) nanocrystals have been synthesized by conventional and a modified size-controlled coprecipitation method and characterized by X-ray diffraction, transmission electron microscopy, vibrating sample magnetometry, and Mossbauer spectroscopy. The control of the oversaturation conditions in the reacting solution, favored by the control of the flow rate at which the reactants were contacted, promoted heterogeneous nucleation and hence crystal growth, as evidenced by XRD measurements. The size-controlled synthesis route also allowed the tuning of the maximum magnetization and the coercivity, which increased by a factor of five. The demagnetization temperature was found to be strongly dependent on the Co-content and crystal size and varied between 106 °C and 540 °C. Mossbauer spectroscopy confirmed the strong influence of the synthesis conditions on the superparamagnetic fraction in the samples.
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机译:通过常规和改性的尺寸控制的共沉淀方法合成CO_XZN_(1-X)Fe_2O_4(0.5 <= x <= 1.0)纳米晶体,其特征在于X射线衍射,透射电子显微镜,振动样品磁体和母腹光谱。通过控制反应物接触的流速的反应溶液中的过饱和溶液中的过饱和条件的控制,促进过均匀成核,因此晶体生长,如XRD测量所证明。尺寸控制的合成路线还允许调谐最大磁化和矫顽力,这增加了五倍。发现去磁温度强烈依赖于共含量和晶体尺寸,在106℃和540℃之间变化。莫斯鲍尔光谱证实了合成条件对样品中超顺磁性分数的强烈影响。
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