Two new phases LaPd${}_{1-x}$Bi${}_2$ and CePd${}_{1-x}$Bi${}_2$ were obtained by growing single crystals in Bi flux. They adopt the tetragonal ZrCuSi${}_2$-type structure and feature Bi-square nets and PbO-type PdBi layers with significant partial Pd occupancy. Bulk superconductivity at 2.1 K and metallic behavior above $T_c$ are observed in LaPd${}_{1-x}$Bi${}_2$. A small residual resistance ratio (RRR) indicates a strong scattering effect induced by the Pd vacancies, which implies an $s$-wave pairing symmetry in LaPd${}_{1-x}$Bi${}_2$. The broadening of the resistivity transition was measured under different magnetic fields demonstrating a high upper critical field of 3 T. Hall effect measurements reveal dominantly electron-like charge carriers and single-band transport behavior in LaPd${}_{1-x}$Bi${}_2$. The paramagnetic CePd${}_{1-x}$Bi${}_2$ is nonsuperconducting but shows antiferromagnetic ordering below 6 K.

• Received 26 August 2013

DOI:https://doi.org/10.1103/PhysRevB.88.144511