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Superconductivity in the C32 Intermetallic Compounds AAl(2-x)Si(x), with A=Ca and Sr, and 0.6<x<1.2

B. Lorenz·J. Lenzi·J. Cmaidalka·R. L. Meng·Y. Y. Sun·Y. Y. Xue·C. W. Chu
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Abstract

The intermetallic compounds AAl2-xSix, where A = Ca, Sr or Ba, crystallize in the C32 structure, same as the recently discovered MgB2 with a high superconducting transition temperature of 39 K. For x = 1, superconductivity has been observed in AAlSi with A = Ca and Sr, but not with A = Ba. The transition temperatures are 7.8 and 5.1 K, respectively for CaAlSi and SrAlSi. The CaAl2-xSix compound system display a Tc-peak at x = 1, a possible x-induced electronic transition at x ~ 0.75 and a possible miscibility gap near x ~ 1.1 which results in a very broad superconducting transition. The Seebeck coefficients of AAlSi indicate that their carriers are predominantly electrons in nature, in contrast to the holes in MgB2.

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B. Lorenz, J. Lenzi, J. Cmaidalka, R. L. Meng, Y. Y. Sun, Y. Y. Xue, C. W. Chu. 2002-08-16. Superconductivity in the C32 Intermetallic Compounds AAl(2-x)Si(x), with A=Ca and Sr, and 0.6<x<1.2. https://doi.org/10.1016/s0921-4534(02)02056-7

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