Electrical Properties and Phase Transitions in Superconducting Quasi-One-Dimensional Chalcogenides InxNb3X4 (X = S, Se, and Te)
✍ Scribed by T. Ohtani; Y. Sano; Y. Yokota
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 413 KB
- Volume
- 103
- Category
- Article
- ISSN
- 0022-4596
No coin nor oath required. For personal study only.
✦ Synopsis
Electrical properties and phase transitions were investigated in the quasi-one-dimensional ternary chalcogenides (\operatorname{In}{x} \mathrm{Nb}{3} X_{4}(X=\mathrm{S}). Se, and (\mathrm{Te} ; x=0.5) for (X=S), and 1.0 for (X=\mathrm{Se}) and (\mathrm{Te})), with resulis indicating that the (\mathrm{In}{\mathrm{r}} \mathrm{Nb}{3} \mathrm{Te}{4}) system has two new kinds of phase transitions. Based on the values of the transition temperatures (T{t}), this system is classified into two groups, i.e., Group 1 samples with (0 \leq x<0.55) having (T_{1}=\approx 40) and (\approx 80 \mathrm{~K}), and Group 2 samples with (0.55<x \leq 1.0) having (T_{1}=\approx 50) and (\approx 140 \mathrm{~K}). Electron diffraction measurements showed the (140-\mathrm{K}) transition to be associated with a charge-density-wave (CDW) formation accompanied by the appearance of a superstructure that can be explained by the commensurate wave vectors (q= \pm\left(!a^{}+b^{}\right)+c^{}), which are slightly larger in the (c^{}) component as compared with those previously observed in (\mathrm{Nb}{3} \mathrm{Te}{4}) of (q= \pm\left(3 a^{}+\frac{\xi}{3} b^{}\right)+) Ic**. The increase in the (r^{*}) component was interpreted as being caused by the increase in Fermi energy duc to (\ln) insertion. 'Thermopower measutements on (\ln {x} \mathrm{Nb}{3} \mathrm{Te}{4}) showed the dominant carriers (o be holes. In itidition. the in, (\mathrm{Nb}{1} \mathrm{Se}{3,84}) system (0.4) (\leq x \leq 1.0) ) showed a new Ci3W-fike transition it (\approx=30 \mathrm{~K}). The superconducting critical temiperature (T{\mathrm{c}}) of (\ln {\mathrm{r}} \mathrm{N}{3} X_{4}) was increased by several degrees when the in content (x) was increased above 0.5 , of (w)3 Atademic Press. Ine.