Robust superconductivity with large upper critical field in Nb2PdS5

Abstract

We report synthesis, structural details, and complete superconducting characterization of very recently discovered [Q. Zhang, Sci. Rep. 3, 1446(2013] Nb 2 PdS 5 new superconductor. The synthesized compound is crystallized in monoclinic structure with C2/m (#12) space group. Bulk superconductivity is seen in both ac/dc magnetic susceptibility and electrical resistivity measurements with superconducting transition temperature (T c ) at 6 K. The upper critical field (H c2 ) being estimated from high field magneto-transport [q(T)H] measurements is above 240 kOe. The estimated H c2 (0) is clearly above the Pauli paramagnetic limit of $1.84T c . Heat capacity (C p ) measurements show clear transition with well defined peak at T c , but with lower jump than as expected for a Bardeen-Cooper-Schrieffer type superconductor. The Sommerfeld constant (c) and Debye temperature (H D ) as determined from low temperature fitting of C P (T) data are 32 mJ/mole-K 2 and 263 K, respectively. Hall coefficients and resistivity in conjugation with electronic heat capacity indicates multiple gap superconductivity signatures in Nb 2 PdS 5 . We also studied the impact of hydrostatic pressure (0-1.97 Gpa) on superconductivity of Nb 2 PdS 5 and found nearly no change in T c for the given pressure range. V C 2014 AIP Publishing LLC. [http://dx

Single gap s-wave superconductivity in Nb2PdS5

“…This value exceeds the Pauli paramagnetic limit Hc 2 (0) = 1.84T c by over 3 times [1][2][3][4]. The anisotropic upper critical field ( ~ 3) along with temperature dependent anisotropy was indicative of possible multiband superconductivity [1,5].…”

“…Polycrystalline sample of Nb 2 PdS 5 were prepared by solid state reaction method as described elsewhere [4]. Resistivity measurement was done using four probe method in a Cryogenic low temperature and high magnetic field system in conjunction with variable temperature insert.…”

“…The anisotropic upper critical field ( ~ 3) along with temperature dependent anisotropy was indicative of possible multiband superconductivity [1,5]. Concepts related to strong spin-orbit scattering and spin triplet pairing mechanism were invoked to explain the highest ever reported H c2 (0)/T c value [4,5]. The high H c2 value and the presence of chalcogen in the layered structure are reminiscent of Chevrel phase compounds such as PbMo 6 S 8 [6,7] and SnMo 6 S 8 [8] but still there is no clarity on the macroscopic origin of superconductivity in Nb 2 PdS 5 .…”

Superconductivity at 4.4 K in PdTe2 Chains of a Ta-Based Compound

“…The discovery of high-temperature superconductivity in low-dimensional systems especially in Curates and Iron-based compounds is well celebrated and most haunted phenomenon in condensed matter physics in recent times [1,2]. Recent observation of superconductivity in a strong spin-orbit coupled 4d and 5d transition metal based compound like (Ta/Nb) x Pd(Te/Se/S) y has been arousing high hopes for researchers due to their high critical field [3][4][5][6][7][8][9]. For a compound Ta 2 Pd x S 5 (x<1), Zhang et al first reported type II superconductivity with T c up to 6K [3].…”

Superconductivity at 4 K in Pd-Deficient Layered Ta2Pd x S6

“…1 National Physical Laboratory, New Delhi-110012, India 2 Sri Murli Manohar Town Post Graduate College Ballia.…”