The formation of precipitates in the ZnCoO system
The formation of precipitates in the ZnCoO system
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DOI：
10.1209/epl/i2005-10191-2
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发表时间：
2005-10
期刊：
影响因子：
1.8
通讯作者：
Hyun-Yong Lee;S. Choi;C. Cho;H. Kim;Se-Young Jeong
中科院分区：
文献类型：
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作者：
Hyun-Yong Lee;S. Choi;C. Cho;H. Kim;Se-Young Jeong
磁性物质如过渡金属或金属氧化物能够通过在磁性半导体中的聚集而表现出铁磁性。采用溶胶-凝胶法制备了Co掺杂ZnO样品，并利用中子衍射和X射线吸收精细结构测量研究了样品中的磁性沉淀。的结构细节，其特征在于通过X射线和中子衍射，并使用Rietveld精化的数据进行解释。掺杂的Co离子在5mol%时被完全取代到ZnO晶格中，但在5mol%以上的Co掺杂形成Co 3 O 4的第二相，并且其中子衍射信号增加到20mol%。每一相的定量计算为55.43重量%。的Co 3 O 4和44.57重量%完全钴取代的氧化锌。在30摩尔%的钴掺杂的样品中，钴金属，以及氧化的钴，在这项研究中被确定。然而，通过X射线衍射没有观察到这些信号。为了验证局部化学键合状态，我们使用扩展的X射线吸收精细结构测量，并通过使用傅立叶分析计算原子间距离来研究沉淀物的形成。
Magnetic matter such as transition metals or metal oxides are able to exhibit ferromagnetism by the clustering in magnetic semiconductors. We fabricated Co-doped ZnO samples using the sol-gel method, and studied the magnetic precipitates in the samples by using both neutron diffraction and X-ray absorption fine-structure measurements. The structural details were characterized by X-ray and neutron diffraction, and the data were interpreted using Rietveld refinement. The doped Co ion was fully substituted into a ZnO lattice at 5 mol%, but the secondary phase of the Co3O4 was formed above 5 mol% of Co doping and its neutron diffraction signal increased up to 20 mol%. The quantitative amounts of each phase were calculated to be 55.43 wt.% of Co3O4 and 44.57 wt.% of fully cobalt-substituted ZnO. In the 30 mol% Co-doped sample, Co metal, as well as oxidized Co, were identified in this study. Those signals, however, were not observed by X-ray diffraction. To verify the local chemical bonding state, we used extended X-ray absorption fine-structure measurement and investigated the formation of precipitates by calculating the inter-atomic distance using Fourier analysis.