Spurious second transition in the heavy-fermion superconductor CePt3Si -: art. no. 212505
Spurious second transition in the heavy-fermion superconductor CePt3Si -: art. no. 212505
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DOI：
10.1103/physrevb.71.212505
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发表时间：
2005-06-01
影响因子：
3.7
通讯作者：
Salamon, MB
中科院分区：
文献类型：
--
作者：
Kim, JS;Mixson, DJ;Salamon, MB
比热研究表明，在重费米子超导体CePt3Si的一些名义上的单相样品中，在T约为0.48K处有明显的第二相转变，T-c=0.75K，在本工作中这也被认为是穿透深度测量中的结构。Ce1-xPt3Si中的Ce缺陷加剧了双跃迁结构，在x>；=2%时变得可重现。电子探针、X射线衍射和金相研究表明，这些缺Ce样品中只有少量的第二相，通过二次电子背散射，其成分与Ce2Pt15Si7相似。该化合物是一种反铁磁体，其C/T峰值在0.4K，量值为22000 mJ(Ce-molK-2)(-1)。因此，在复杂的Ce-Pt-Si三元相图中，在超导转变以下的比热中偶尔观察到结构的原因是在样品的电弧熔化或退火过程中，Ce的质量损失只有十分之几。
Specific heat studies have shown a distinct second transition at T approximate to 0.48 K in some nominally single-phase samples of the heavy Fermion superconductor CePt3Si, T-c=0.75 K, which in the current work is also seen as structure in penetration depth measurements. The double transition structure is accentuated by a Ce deficiency in Ce1-xPt3Si, becoming reproducible for x >= 2%. Electron microprobe, x-ray diffraction, and metallography studies of these Ce-deficient samples show only a minor amount of second phase which, by secondary electron backscattering, is similar in composition to Ce2Pt15Si7. This compound is an antiferromagnet with a peak in C/T at 0.4 K with a magnitude of 22000 mJ (Ce-mol K-2)(-1). Thus, in the complexity of a the Ce-Pt-Si ternary phase diagram, the cause for the occasionally observed structure in the specific heat below the superconducting transition is a few tenths of a percent mass loss of Ce during arc-melting or annealing of the sample.