Superconductivity in BaCuxSi2-x (0.2 ≤ x ≤ 0.6) with AlB2-type structure

We discovered superconductivity in BaCuxSi2-x (0.2 ≤ x ≤ 0.6) with the maximum Tc of 3 K. The synthesized samples have AlB2-type structure. We measured the physical properties of BaCu0.3Si1.7 in the superconducting state as functions of temperature and magnetic field. Magnetization vs. magnetic field (M–H) curves show typical type-II superconducting behavior. Superconducting parameters Hc1(0), Hc2(0), λ(0), ξ(0), and κGL are determined to be about 20 Oe, 22 kOe, 570 nm, 12 nm, and 48, respectively. Lattice constants a and c and the Tc value depend on Cu concentration, x, Tc decreases with increasing x.