Successive superconducting transitions inTa2S2Cstudied by electrical resistivity and nonlinear ac magnetic susceptibility

Abstract

Ta2S2C compound undergoes superconducting transitions at T cl = 3.60 ± 0.02 K and Tcu = 9.0 ± 0.2 K. The nature of successive superconducting transitions has been studied from electrical resistivity, linear and nonlinear AC magnetic susceptibilities. The resistivity ρ at H = 0 shows a local maximum near Tcu, a kink-like behavior around T cl , and reduces to zero at below T0 = 2.1 K. The ln T dependence of ρ is observed at H = 50 kOe at low temperatures, which is due to two-dimensional weak-localization effect. Below Tcu a two-dimensional superconducting phase occurs in each TaC layer. The linear and nonlinear susceptibilities χ

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

“…Understanding nonlinear effects allowed decisive breakthrough in condensed matter physics. Spin glasses [1,2,3,4,5,6], ferroelectric, freezing, or dipolar glass transitions [7,8,9,10,11,12,13,14,15,16,17,18,19], isotropic-liquid crystal transition [20,21] or binary mixtures [22,23], superconductivity [24,25,26,27,28,29], field [30,31,32,33,34] or heating [35,36,37,38,39,40] effects in electrical transport, heating due to electric field excitation of supercooled liquids [41,42] are a few among many topics where non linear measurements have proven to be a precious tool.…”