Synthesis and thermodynamic properties of superconducting NdPd1-δBi2 (δ∼0.23) single crystals

Abstract The interesting phenomena induced by the interaction between local moments and itinerant electrons in 4 f compounds have attracted extensive attention for many years. Here, we report the synthesis of a new 4 f compound, i.e. NdPd 1- δ Bi 2 ( δ ∼0.23) which is superconducting with a transition temperature T c around 3.2 K. A comprehensive investigation of the thermodynamic properties suggests NdPd 1- δ Bi 2 is also an anti-ferromagnet with the Neel temperature T N ∼4 K. Moreover, its high-temperature paramagnetic state is characterized by an enhanced heat capacity with a Sommerfeld coefficient γ over 300 mJ mol −1  K −2 , which presumably results from Nd 3+ crystal-electric-field splitting rather than the Kondo effect. In the superconducting state, the suppression of superconductivity with field increasing for H || c is faster in comparison with H || ab , resulting in a moderate upper critical field anisotropy with Γ = H c 2 ( 0 K , ‖ a b ) / H c 2 ( 0 K , ‖ c ) ∼2.6. Collectively, NdPd 1- δ Bi 2 may serve as an intriguing system to study the interplay among magnetic order, Kondo effect, and superconductivity in 4 f compounds.