Superconductivity in the AIB2-type ternary rare-earth silicide YbGa1.1Si0.9

A novel ternary intermetallic compound, YbGa1.1Si0.9, was synthesized using a two-step process of Ar-arc melting and annealing. YbGa1.1Si0.9 was found to crystallize in the AlB2-type structure (space group P6/mmm, No. 191, Z = 1), in which Si and Ga atoms are arranged in chemically disordered honeycomb layers and Yb atoms are intercalated between the honeycomb layers. The electrical resistivity and dc magnetization measurements revealed that YbGa1.1Si0.9 is a type II superconducting material with a superconducting critical temperature of 2.4 K. The temperature dependence of magnetic susceptibility demonstrates that Yb atoms in YbGa1.1Si0.9 are divalent.