| α-Fe_2O_3纳米粒子Morin相变的Raman光谱研究 |
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| 引用本文： | 王桂华,施建成,杨海峰,王欣,章宗穰.α-Fe_2O_3纳米粒子Morin相变的Raman光谱研究[J].光散射学报,2001,13(4):220-225. |
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| 作者姓名： | 王桂华 施建成 杨海峰 王欣 章宗穰 |
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| 作者单位： | 上海师范大学化学系,上海市桂林路100号,200234 |
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| 摘 要： | 本文首次用Raman光谱法研究了粒子尺寸和Co2 +包附对α-Fe2 O3纳米粒子Morin相变温度TM的影响机制。测量结果显示纳米粒子α -Fe2 O3的振动模相对大块样品发生了红移和宽化 ,粒子愈小红移和宽化愈显著。表明表面Fe3+离子与配位氧离子的键距增大 ,键长呈从体相Fe-O键长过渡到表面Fe -O键长的某种分布。这种小尺寸引起的键长改变导致α -Fe2 O3粒子的单离子各向异性能减小 ,因此降低了样品的TM。分析显示Co2 +包附导致α -Fe2 O3粒子TM 的大幅下降可能是由单离子各向异性的减小和Co2 +与Fe3+之间的磁偶极子相互作用各向异性共同作用的结果
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| 关 键 词： | α-Fe2O3纳米粒子 Morin相变 Raman光谱 |
| 文章编号： | 1004-5929(2001)04-0220-06 |
| 修稿时间： | 2001年7月31日 |
A Study of Raman Spectroscopy on the Morin Transition of α-Fe2O3 Nanoparticles |
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| WANG Gui-hua,SHI Jian-cheng,YANG Hai-feng,WANG Xin,ZHANG Zong-rang.A Study of Raman Spectroscopy on the Morin Transition of α-Fe2O3 Nanoparticles[J].Chinese Journal of Light Scattering,2001,13(4):220-225. |
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| Authors: | WANG Gui-hua SHI Jian-cheng YANG Hai-feng WANG Xin ZHANG Zong-rang |
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| Abstract: | The influence of the size and surface coating on the Morin transition (T M) of α-Fe 2O 3 nanoparticles has been investigated by magnetic measurement and Raman spectroscopy The results of the magnetic measurement show that T M varies from 264 K to 92 K with decrease in the size of the particles Whereas Co 2+ coating made T M of the particles down even more The Raman spectra obtained indicates that the bands were broadened and shifted down by ca 2-14 cm -1 with decrease of the particle size and Co 2+ coating, which imply that the Fe-O bonds of the particles were weakened It may give rise to the decrease of the single ion anisotropy of α-Fe 2O 3 particles, resulting in the decrease in T M The largest decrease in T M of Co 2+ coating α-Fe 2O 3 particles is probably caused by the co-action of the decrease in the single ion anisotropy and magnetic dipole anisotropy |
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| Keywords: | Fe 2O 3 nanoparticles Morin transition Raman spectroscopy |
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