Impact of Ni doping on critical parameters of PdTe superconductor

Abstract

We report the effect of Ni doping on superconductivity of PdTe. The superconducting parameters like critical temperature (Tc), upper critical field (Hc2) and normalized specific-heat jump (ΔC/γTc) are reported for Ni doped Pd1−xNixTe. Samples of series Pd1−xNixTe with nominal compositions x = 0, 0.01, 0.05, 0.07, 0.1, 0.15, 0.2, 0.3 and 1.0 are synthesized via the vacuum shield solid state reaction route. All the studied samples of Pd1−xNixTe series are crystallized in a hexagonal crystal structure as refined by the Rietveld method to space group P63/mmc. Both the electrical resistivity and magnetic measurements revealed that Tc decreases with increasing Ni concentration in Pd1−xNixTe. Magnetotransport measurements suggest that flux is better pinned for 20% Ni doped PdTe as compared to other compositions of Pd1−xNixTe. The effect and contribution of Ni 3d electron to electronic structure and density of states near the Fermi level in Pd1−xNixTe are also studied using first-principle calculations within the spin polarized local density approximation. The overlap of bands at the Fermi level for NiTe is larger as compared to PdTe. Also the density of states just below the Fermi level (in conduction band) drops much lower for PdTe than as for NiTe. In summary, Ni doping in Pd1−xNixTe superconductor suppresses superconductivity moderately and also Ni is of non-magnetic character in these compounds.