Synthesis, Crystal Structure, and Electrical Conductivity of Pd-intercalated NbSe2

Abstract

New intercalated compounds PdxNbSe2 (x=0-0.17) were synthesized via solid-state reaction. They possess the parent structure of 2H-NbSe2 and crystalize in the hexagonal space group of P63/mmc. The intercalated Pd occupies the octahedral position in the van der Waals gaps of 2H-NbSe2. Unit cell parameter c increases linearly with the Pd content, while a is nearly unchanged. The lattice parameter of Pd0.17NbSe2 (a=b=0.34611(2) nm, c= 1.27004(11) nm) is identified by single crystal X-ray diffraction. The intercalated Pd stabilizes the crystal structure of NbSe2 by connecting the adjacent Nb-Se layers with [PdSe6] octahedra and leads to the enhanced thermostability in air. Temperature dependence of electric resistivity reveals that the residual resistivity ratio of PdxNbSe2 monotonically decreases with addition of the intercalated Pd content. The decreased superconducting critical temperature of PdxNbSe2 indicates the suppression effect of Pd intercalation on the superconductivity in the host NbSe2.