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arXiv 0707.0655cond-mat.mtrl-scicond-mat.str-el
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Cr掺杂SrTiO3的阻变:X射线吸收光谱研究

Resistive Switching in Cr doped SrTiO3: An X-ray Absorption Spectroscopy study

B. P. Andreasson, M. Janousch, U. Staub, G. I. Meijer, B. Delley

摘要:

利用X射线吸收光谱研究了掺铬钛酸锶(Cr:SrTiO 3)的电导和阻变的微观起源。在Cr K边缘处的X射线吸收近边光谱(XANES)中的差异表明,在施加电场之后,在我们的样品装置的阳极下方,Cr的价态从3+变为4+。空间分辨X射线荧光显微镜($μ$ -XRF)的地图显示,Cr 4+区域从阳极Cr:SrTiO 3界面后,已实现的导电状态缩回。该界面区域的研究与扩展的X射线吸收精细结构(EXAFS)和结果进行了比较,从密度泛函理论(DFT)计算得到的结构参数。他们证实,在界面处引入了氧空位,该氧空位位于以Cr为中心的八面体处。据建议,开关状态不是由于铬的价态变化,但引起的界面处的氧空位的变化。

英文摘要:

X-ray absorption spectroscopy was used to study the microscopic origin of conductance and resistive switching in chromium doped strontium titanate (Cr:SrTiO3). Differences in the x-ray absorption near edge spectroscopy (XANES) at the Cr K-edge indicate that the valence of Cr changes from 3+ to 4+ underneath the anode of our sample device after the application of an electric field. Spatially resolved x-ray fluorescence microscopy ($μ$-XRF) maps show that the Cr4+ region retracts from the anode-Cr:SrTiO3 interface after a conducting state has been achieved. This interface region is studied with extended x-ray absorption fine structure (EXAFS) and the results are compared with structural parameters obtained from density functional theory (DFT) calculations. They confirm that oxygen vacancies which are localized at the octahedron with a Cr at its center are introduced at the interface. It is proposed that the switching state is not due to a valence change of chromium but caused by changes of oxygen vacancies at the interface.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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