arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0705.4659cond-mat.supr-concond-mat.str-el
收藏

specific heat的PDMATHAAC Sb $_{12}$中两个超导转变的性质:晶体研磨的影响

On the nature of two superconducting transitions in the specific heat of PrOs$_4$Sb$_{12}$: Effects of crystal grinding

M. E. McBriarty, P. Kumar, G. R. Stewart, B. Andraka

摘要:

比热,直流和交流磁化率的大单晶的PrOs $_4$锑$_{12}$,研磨后,其粉末的报告。晶体的室温有效顺磁矩与Pr $^{3+}$离子构型和Pr亚晶格的完全占据一致。该晶体在比热方面表现出两种明显的异常,并且在$C/T$中表现出大于1000 mJ/K $^2$ mol的总体不连续性。上过渡区(在$T_{c1}$)修圆,与之前的报告一致。$T_{c2}$处的异常非常尖锐,与晶体的良好质量一致。我们观察到$χ$“中的肩峰和$χ$ "中的两个峰低于$T_{c1}$。然而,在$χ$中没有较低温度转变的特征。PrOs $_4$ Sb $_{12}$对研磨极其敏感,这抑制了比热和磁化率的上超导转变。在粉末样品中,$ΔC/T_{c}$降低至140 mJ/K $^2$ mol。现有的数据,地面,抛光,切片晶体表明存在的长度尺度为100 $μ$,表征高温超导相。

英文摘要:

Specific heat, dc- and ac-magnetic susceptibility are reported for a large single crystal of PrOs$_4$Sb$_{12}$ and, after grinding, its powder. The room temperature effective paramagnetic moment of the crystal was consistent with the Pr$^{3+}$ ionic configuration and full occupancy of the Pr-sublattice. The crystal showed two distinct anomalies in the specific heat and an overall discontinuity in $C/T$ of more than 1000 mJ/K$^2$mol. The upper transition (at $T_{c1}$) was rounded, in an agreement with previous reports. The anomaly at $T_{c2}$ was very sharp, consistent with a good quality of the crystal. We observed a shoulder in $χ$' and two peaks in $χ$'' below $T_{c1}$. However, there were no signatures in $χ$' of the lower temperature transition. PrOs$_4$Sb$_{12}$ is extremely sensitive to grinding, which suppresses the upper superconducting transition in both the specific heat and magnetic susceptibility. $ΔC/T_{c}$ was reduced to 140 mJ/K$^2$ mol in the powdered sample. Existing data on ground, polished, and sliced crystals suggests the existence of a length scale of order 100 $μ$, characterizing the higher temperature superconducting phase.

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。

↑