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Abstract: Experimental measurements of the residual resistivity $ hox$ of the binaryalloy system Fe$ {1-x}$Cr$ x$ have shown an anomalous concentration dependencewhich deviates significantly from Nordheim-s rule. In the low $x < 10%$ Crconcentration regime the resistivity has been found to increase linearly with$x$ until $\approx$ 10% Cr where the resistivity reaches a plateau persistingto $\approx$ 20% Cr. In this paper we present $ab$-$initio$ calculations of$ hox$ which explain this anomalous behavior and which are based on theKorringa-Kohn-Rostoker KKR method in conjunction with the Kubo-Greenwoodformalism. Furthermore we are able to show that the effects of short-rangeordering or clustering have little effect via our use of the nonlocalcoherent-potential approximation NL-CPA. For the interpretation of theresults we study the alloys- electronic structure by calculating the Blochspectral function particularly in the vicinity of the Fermi energy. From theanalysis of our results we infer that a similar behavior of the resistivityshould also be obtained for iron-rich Fe$ {1-x}$V$ x$ alloys - an inferenceconfirmed by further explicit resistivity calculations. Both of these alloysystems belong to the same branch of the famous Slater-Pauling plot and wepostulate that other alloy systems from this branch should show a similarbehavior. Our calculations show that the appearance of the plateau in theresistivity can be attributed to the dominant contribution of minority spinelectrons to the conductivity which is nearly unaffected by increase in Cr-Vconcentration $x$ and we remark that this minority spin electron feature isalso responsible for the simple linear variation of the average moment in theSlater-Pauling plot for these materials.



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

Fuente: https://arxiv.org/







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