Superconducting properties of Pr-based Filled skutterudite PrRu${}_4$As${}_{12}$

Abstract

We report on systematic study of superconducting characteristics and Pr crystalline-electric-field (CEF) levels of filled-skutterudite \pra ($T_{\mathrm{c}}$ = 2.33 K). The temperature dependences of the upper critical field $H_{c2}$ and the Ginzburg-Landau (Maki) parameter ${\kappa }_2$ suggest an s-wave clean-limit superconductivity. The electronic specific heat coefficient $\gamma \sim 95$ mJ/K${}^2$mol, being $\sim 1.5$ times larger than that for \lra, indicates $4f$-originating quasiparticle mass enhancement. Magnetic susceptibility $\chi (T)$ indicates that the CEF ground state is a ${\Gamma }_1$ singlet and a ${\Gamma }_4^{(1)}$ triplet first excited state lies at ${\Delta }_{\mathrm{CEF}}\sim 30$ K above. Systematic comparison among \pos, \prs, \pra and La-based reference compounds suggests that inelastic exchange- and aspherical-charge-scatterings of conduction electrons from CEF-split $4f$ levels play an essential role for the quasiparticle mass enhancement and the value of $T_{\mathrm{c}}$ in the Pr-based filled skutterudites.

4 pages, 6 figures

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Cited by in corpus (5)

• Superconductivity in the New Platinum Germanides MPt4Ge12 (M = Rare-earth and Alkaline-earth Metals) with Filled Skutterudite Structure
• Superfluid Density and Energy Gap-Function of Superconducting PrPt4Ge12
• Multiband superconductivity in PrPt4Ge12 single crystals
• Probing the superconductivity of PrPt4Ge12 through Ce substitution
• Broken time-reversal symmetry in superconducting Pr${}_{1-x}$La${}_x$Pt${}_4$Ge${}_{12}$