title: Superconductivity and physical properties of CaPd2Ge2 single crystals.
abstract: We present the superconducting and normal state properties of CaPd(2)Ge(2) single crystals investigated by magnetic susceptibility χ, isothermal magnetization M, heat capacity Cp, in-plane electrical resistivity ρ and London penetration depth λ versus temperature T and magnetic field H measurements. Bulk superconductivity is inferred from the ρ(T) and Cp(T) data. The ρ(T) data exhibit metallic behavior and a superconducting transition with T(c onset) = 1.98 K and zero resistivity at T(c 0) = 1.67 K. The χ(T) reveals the onset of superconductivity at 2.0 K. For T > 2.0 K, the χ(T) and M(H) are weakly anisotropic paramagnetic with χ(ab) > χ(c). The Cp(T) data confirm the bulk superconductivity below T(c) = 1.69(3) K. The superconducting state electronic heat capacity is analyzed within the framework of a single-band α-model of BCS superconductivity and various normal and superconducting state parameters are estimated. Within the α-model, the Cp(T) data and the ab plane λ(T) data consistently indicate a moderately anisotropic s-wave gap with Δ(0)/k(B)T(c) ≈ 1.6, somewhat smaller than the BCS value of 1.764. The relationship of the heat capacity jump at Tc and the penetration depth measurement to the anisotropy in the s-wave gap is discussed.
authors.affiliation: Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA. Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner Platz 1, D-14109 Berlin, Germany.
authors.forename: V K
authors.initials: VK
authors.lastname: Anand
authors.forename: H
authors.initials: H
authors.lastname: Kim
authors.forename: M A
authors.initials: MA
authors.lastname: Tanatar
authors.forename: R
authors.initials: R
authors.lastname: Prozorov
authors.forename: D C
authors.initials: DC
authors.lastname: Johnston