Study on successive superconducting transitions in Ta${}_2$S${}_2$C from electrical resistivity and nonlinear AC magnetic susceptibility

Abstract

Ta${}_2$S${}_2$C compound undergoes superconducting transitions at $T_{cl}=3.60\pm 0.02$ K and $T_{cu}=9.0\pm 0.2$ K. The nature of successive superconducting transitions has been studied from electrical resistivity, linear and nonlinear AC magnetic susceptibilities. The resistivity $\rho$ at $H$ = 0 shows a local maximum near $T_{cu}$, a kink-like behavior around $T_{cl}$, and reduces to zero at below $T_0$ = 2.1 K. The $\ln T$ dependence of $\rho$ is observed at $H$ = 50 kOe at low temperatures, which is due to two-dimensional weak-localization effect. Below $T_{cu}$ a two-dimensional superconducting phase occurs in each TaC layer. The linear and nonlinear susceptibilities ${\chi }_1^{\prime \prime }$, ${\chi }_3^{\prime }$, ${\chi }_5^{\prime }$, and ${\chi }_7^{\prime }$ as well as the difference $\delta \chi$ ($={\chi }_{FC}-{\chi }_{ZFC}$) between the FC and ZFC susceptibilities, start to appear below 6.0 K, the onset temperature of irreversibility. A drastic growth of the in-plane superconducting coherence length below 6.0 K gives rise to a three-dimensional superconducting phase below $T_{cl}$, through interplanar Josephson couplings between adjacent TaC layers. The oscillatory behavior of ${\chi }_3^{\prime \prime }$, ${\chi }_5^{\prime \prime }$, and ${\chi }_7^{\prime \prime }$ below $T_{cl}$ is related to the nonlinear behavior arising from the thermally activated flux flow.

11 pages, 10 figures, Physical Review B (accepted for publication)

References in corpus (2)

• Third Harmonics of the AC Magnetic Susceptibility: a method for the study of flux dynamics in High Temperature Superconductors
• Successive superconducting transitions and Anderson localization effect in Ta${}_2$S${}_2$C

Cited by in corpus (1)

• A method for measuring the nonlinear response in dielectric spectroscopy through third harmonics detection