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arXiv 0903.3560cond-mat.supr-concond-mat.str-el
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Ba(Fe $_{1-x}$ Co $_{x}$)$_2$ As $_2$结构与磁性相互作用的中子散射研究

A neutron scattering study of the interplay between structure and magnetism in Ba(Fe$_{1-x}$Co$_{x}$)$_2$As$_2$

C. Lester, Jiun-Haw Chu, J. G. Analytis, S. Capelli, A. S. Erickson, C. L. Condron, M. F. Toney, I. R. Fisher, S. M. Hayden

摘要:

用单晶中子衍射方法研究了电子掺杂超导体Ba(Fe $_{1-x}$ Co $_x$)$_2$ As $_2$的磁性和结构相图。热容量和电阻率的测量表明,Co掺杂该系统分裂的组合反铁磁和结构的转变存在于BaFe $_2$作为$_2$成两个不同的转变。当$x$ =0.025时,我们发现上相变发生在高温四方晶系和低温正交晶系之间,($T_{\mathrm{TO}}=99 \pm 0.5$ K),反铁磁相变发生在$T_{\mathrm{AF}}=93 \pm 0.5$ K。我们发现,掺杂迅速抑制反铁磁性,与反铁磁秩序消失在$x \approx 0.055$。然而,存在反铁磁性和超导性共存的区域。从中子散射和X射线衍射的结构布拉格峰的温度依赖性中可以看出反铁磁转变的效果。我们由此推断,反铁磁性与晶格之间存在强耦合。

英文摘要:

Single crystal neutron diffraction is used to investigate the magnetic and structural phase diagram of the electron doped superconductor Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$. Heat capacity and resistivity measurements have demonstrated that Co doping this system splits the combined antiferromagnetic and structural transition present in BaFe$_2$As$_2$ into two distinct transitions. For $x$=0.025, we find that the upper transition is between the high-temperature tetragonal and low-temperature orthorhombic structures with ($T_{\mathrm{TO}}=99 \pm 0.5$ K) and the antiferromagnetic transition occurs at $T_{\mathrm{AF}}=93 \pm 0.5$ K. We find that doping rapidly suppresses the antiferromagnetism, with antiferromagnetic order disappearing at $x \approx 0.055$. However, there is a region of co-existence of antiferromagnetism and superconductivity. The effect of the antiferromagnetic transition can be seen in the temperature dependence of the structural Bragg peaks from both neutron scattering and x-ray diffraction. We infer from this that there is strong coupling between the antiferromagnetism and the crystal lattice.

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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