arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2001.06396cond-mat.mtrl-sci
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Cr $_2$ GeC磁各向异性的X射线磁圆二色性和\textit{ab initio}计算

Magnetic anisotropy in Cr$_2$GeC investigated by X-ray magnetic circular dichroism and \textit{ab initio} calculations

Martin Magnuson, Maurizio Mattesini

摘要:

采用元素选择性、偏振和温度依赖性、软X射线吸收光谱和X射线磁性圆二色性研究了三元MAX相Cr $_{2}$ GeC的磁性。测量结果表明,沿$c$轴的六方结构的反铁磁Cr-Cr耦合调制的纳米层压$ab$ -基面的铁磁有序。弱铬磁矩在纳米层压平面中比沿垂直轴强一个数量级。理论上,一个小的但值得注意的,非自旋共线的分量解释了沿$c$轴的非完美自旋补偿的存在。如在这项工作中所示,这种自旋畸变产生的单位细胞内的整体剩余自旋力矩类似的亚铁磁体。由于不同的竞争磁相互作用,电子相关性和温度效应都需要考虑,以实现正确的理论描述的Cr $_{2}$ GeC的磁性能。

英文摘要:

The magnetism in the inherently nanolaminated ternary MAX-phase Cr$_{2}$GeC is investigated by element-selective, polarization and temperature-dependent, soft X-ray absorption spectroscopy and X-ray magnetic circular dichroism. The measurements indicate an antiferro-magnetic Cr-Cr coupling along the $c$-axis of the hexagonal structure modulated by a ferromagnetic ordering in the nanolaminated $ab$-basal planes. The weak chromium magnetic moments are an order of magnitude stronger in the nanolaminated planes than along the vertical axis. Theoretically, a small but notable, non-spin-collinear component explains the existence of a non-perfect spin compensation along the $c$-axis. As shown in this work, this spin distortion generates an overall residual spin moment inside the unit cell resembling that of a ferri-magnet. Due to the different competing magnetic interactions, electron correlations and temperature effects both need to be considered to achieve a correct theoretical description of the Cr$_{2}$GeC magnetic properties.

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