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Growth of monodisperse nanospheres of MnFe_2O_4 with enhanced magnetic and optical properties 下载免费PDF全文
M.Yasir Rafique 潘礼庆 Qurat-ul-ain Javed M.Zubair Iqbal 邱红梅 M.Hassan Farooq 郭振刚 M.Tanveer 《中国物理 B》2013,(10):453-459
Highly dispersive nanospheres of MnFe204 are prepared by template free hydrothermal method. The nanospheres have 47.3-nm average diameter, narrow size distribution, and good crystallinity with average crystallite size about 22 nm. The reaction temperature strongly affects the morphology, and high temperature is found to be responsible for growth of uniform nanospheres. Raman spectroscopy reveals high purity of prepared nanospheres. High saturation magnetization (78.3 emu/g), low coercivity (45 Oe, 10e = 79.5775 A.cm-1), low remanence (5.32 emu/g), and high anisotropy constant 2.84 × 10^4 J/m3 (10 times larger than bulk) are observed at room temperatures. The nearly snperparamagnetic behavior is ~ spin due to comparable size of nanospheres with superparamagnetic critical thameter Dcr spm The high value of Keff may be due to coupling between the pinned moment in the amorphous shell and the magnetic moment in the core of the nanospheres. The nanospheres show prominent optical absorption in the visible region, and the indirect band gap is estimated to be 0.98 eV from the transmission spectrum. The prepared Mn ferrite has potential applications in biomedicine and photocatalysis. 相似文献
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低真空条件下制备的银薄膜的电阻率特性及结构 总被引:1,自引:0,他引:1
研究了在2.2 Pa低真空条件下用直流溅射法制备的银薄膜的电阻率特性和薄膜结构.实验表明,薄膜厚度对薄膜电阻率有显著影响,随膜厚的增加薄膜电阻率降低,在膜厚大于200 nm时趋于稳定,电阻率为2.54×10-8Ω.m.薄膜表面和晶粒间界对传导电子的散射导致了银薄膜电阻率的尺寸效应.研究结果表明,可以在2.2 Pa的低真空条件下制备金属银薄膜,将银靶用于目前大学物理实验课中金属薄膜制备及金属薄膜电阻率测量实验是可行的. 相似文献
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The ferromagnetic semiconductor La2NiMnO6 (LNMO) has recently received much attention due to its high Curie temperature (Tc 280 K), which is close to room temperature. We prepared single-phase LNMO polycrystaUine samples and investigated the temperature- and field-dependent magnetic behaviors of bulk LNMO. Between Tc and T* = 300 K, we observed upward and downward deviations from the Curie-Weiss law for high and low magnetic fields, respectively. From the electron spin resonance results, we can exclude the existence of the Griffiths phase. On the contrary, our results indicate that the abnormal magnetic behaviors might be induced by antisite phase boundaries with antiferromagnetic interaction. 相似文献