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arXiv 1804.03215cond-mat.supr-concond-mat.mtrl-sci
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压力对La3Co4Sn13结构和超导转变的影响

Pressure effects on the structural and superconducting transitions in La3Co4Sn13

L. Mendonça-Ferreira, F. B. Carneiro, M. B. Fontes, E. Baggio-Saitovitch, L. S. I. Veiga, J. R. L. Mardegan, J. Strempfer, M. M. Piva, P. G. Pagliuso, R. D. dos Reis, E. M. Bittar

摘要:

La 3Co 4Sn 13是一种超导材料,其转变温度为2.70 K,在T ~* ~ 150 K呈现超晶格结构转变,这是该类化合物的共同特征。然而,对于这种材料,目前尚不清楚在T* 下的晶格畸变是由电荷密度波(CDW)还是由不同的微观起源引起的。有趣的是,有人建议在同构非磁性金属间化合物中,通过结合化学和外部压力,T* 可以被抑制到零温度,并且在这些临界掺杂/压力附近观察到量子临界点。我们的研究表明,在单晶La 3Co 4Sn 13上施加压力提高了Tc,降低了T*。在电阻率测量中,我们观察到P > 0.6 GPa时T* 周围冷却/加热循环的热滞后回线,这在X射线衍射数据中看不到。电测量中的滞后可能是由于CDW相对杂质/缺陷的钉扎,而超晶格结构转变在压力下保持其环境压力二级转变性质。根据我们的实验,我们估计T* 在5.5 GPa左右消失,尽管在2.53 GPa以下没有观察到量子临界行为。

英文摘要:

La3Co4Sn13 is a superconducting material with transition temperature at Tc = 2.70 K, which presents a superlattice structural transition at T* ~ 150 K, a common feature for this class of compounds. However, for this material, it is not clear that at T* the lattice distortions arise from a charge density wave (CDW) or from a distinct microscopic origin. Interestingly, it has been suggested in isostructural non-magnetic intermetallic compounds that T* can be suppressed to zero temperature, by combining chemical and external pressure, and a quantum critical point is argued to be observed near these critical doping/pressure. Our study shows that application of pressure on single-crystalline La3Co4Sn13 enhances Tc and decreases T*. We observe thermal hysteresis loops for cooling/heating cycles around T* for P > 0.6 GPa, in electrical resistivity measurements, which are not seen in x-ray diffraction data. The hysteresis in electrical measurements may be due to the pinning of the CDW phase to impurities/defects, while the superlattice structural transition maintains its ambient pressure second-order transition nature under pressure. From our experiments we estimate that T* vanishes at around 5.5 GPa, though no quantum critical behavior is observed up to 2.53 GPa.

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