Superconductivity and Physical Properties of CaPd₂Ge₂ Single Crystals


We present the superconducting and normal state properties of CaPd2Ge2single 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 Tc onset = 1.98K and zero resistivity at Tc 0 = 1.67 K. The χ(T) reveals the onset of superconductivity at 2.0K. For T > 2.0 K, the χ(T) and M(H) are weakly anisotropic paramagnetic with χab > χc. The Cp(T) data confirm the bulk superconductivity below Tc = 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)/kBTc ≈ 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.



Keywords and Phrases

Anisotropic Gap; Penetration Depth; Pnictides; Superconductivity

International Standard Serial Number (ISSN)

1361-648X; 0953-8984

Document Type

Article - Journal

Document Version


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© 2014 IOP Publishing, All rights reserved.

Publication Date

08 Oct 2014