arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0811.2303cond-mat.mtrl-sci
收藏

铁磁合金中的电子输运和Slater-Pauling曲线

Electronic transport in ferromagnetic alloys and the Slater-Pauling Curve

S. Lowitzer, D. Ködderitzsch, H. Ebert, J. B. Staunton

摘要:

对二元合金系Fe $_{1-x}$ Cr $_x$的剩余电阻率$ρ(x)$的实验测量表明,它与诺德海姆规则有明显的偏离。在低($x < 10%$)Cr浓度范围内,已发现电阻率随$x$线性增加,直到$\approx$ 10% Cr,其中电阻率达到持续到$\approx$ 20% Cr的平台。在本文中,我们提出了$ab$ - $initio$计算的$ρ(x)$解释这种反常行为,并结合Kubo-Greenwood形式主义的Korringa-Kohn-Rostoker(KKR)方法的基础上。此外,我们能够表明,短程有序或集群的影响,通过我们使用的非局部相干势近似(NL-CPA)的影响很小。为了解释这些结果,我们通过计算Bloch谱函数,特别是在费米能附近,研究了合金的电子结构。从我们的结果的分析,我们推断,一个类似的行为的电阻率也应该得到富铁的Fe $_{1-x}$ V $_x$合金-进一步明确的电阻率计算证实的推断。这两个合金系统属于著名的斯莱特-鲍林图的同一分支,我们假设来自该分支的其他合金系统应该表现出类似的行为。我们的计算表明,在电阻率的平台的外观可以归因于少数自旋电子的主要贡献的电导率,这是几乎不受影响的增加Cr/V浓度$x$,我们注意到,这种少数自旋电子的功能也是负责简单的线性变化的平均时刻在斯莱特-鲍林图为这些材料。

英文摘要:

Experimental measurements of the residual resistivity $ρ(x)$ of the binary alloy system Fe$_{1-x}$Cr$_x$ have shown an anomalous concentration dependence which deviates significantly from Nordheim's rule. In the low ($x < 10%$) Cr concentration regime the resistivity has been found to increase linearly with $x$ until $\approx$ 10% Cr where the resistivity reaches a plateau persisting to $\approx$ 20% Cr. In this paper we present $ab$-$initio$ calculations of $ρ(x)$ which explain this anomalous behavior and which are based on the Korringa-Kohn-Rostoker (KKR) method in conjunction with the Kubo-Greenwood formalism. Furthermore we are able to show that the effects of short-range ordering or clustering have little effect via our use of the nonlocal coherent-potential approximation (NL-CPA). For the interpretation of the results we study the alloys' electronic structure by calculating the Bloch spectral function particularly in the vicinity of the Fermi energy. From the analysis of our results we infer that a similar behavior of the resistivity should also be obtained for iron-rich Fe$_{1-x}$V$_x$ alloys - an inference confirmed by further explicit resistivity calculations. Both of these alloy systems belong to the same branch of the famous Slater-Pauling plot and we postulate that other alloy systems from this branch should show a similar behavior. Our calculations show that the appearance of the plateau in the resistivity can be attributed to the dominant contribution of minority spin electrons to the conductivity which is nearly unaffected by increase in Cr/V concentration $x$ and we remark that this minority spin electron feature is also responsible for the simple linear variation of the average moment in the Slater-Pauling plot for these materials.

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。

↑