Pairing symmetry of an intermediate valence superconductor CeIr3 investigated using muSR measurements

Abstract

We have investigated the bulk and microscopic properties of the rhombohedral intermediate valence superconductor CeIr${}_3$ by employing magnetization, heat capacity, and muon spin rotation and relaxation ($\mu$SR) measurements. The magnetic susceptibility indicates bulk superconductivity below $T_{\mathrm{C}}=3.1$~K. Heat capacity data also reveal a bulk superconducting transition at $T_{\mathrm{C}}=3.1$~K with a second weak anomaly near 1.6~K. At $T_{\mathrm{C}}$, the jump in heat capacity $\Delta C$/$\gamma T_{\mathrm{C}}\sim 1.39(1)$, is slightly less than the BCS weak coupling limit of 1.43. Transverse-field $\mu$SR measurements suggest a fully gapped, isotropic, $s$-wave superconductivity with 2$\Delta (0)/k_{\mathrm{B}}{T}_{\mathrm{C}}=3.76(3)$, very close to 3.56, the BCS gap value for weak-coupling superconductors. From the temperature variation of magnetic penetration depth, we have also determined the London penetration depth ${\lambda }_{\mathrm{L}}(0)=435(2)$~nm, the carriers' effective mass enhancement $m^{\ast }=1.69(1)m_{\mathrm{e}}$ and the superconducting carrier density $n_{\mathrm{s}}=2.5(1)\times 10^{26}$ carriers m${}^{-3}$. The fact that LaIr${}_3$, with no $4f$-electrons, and CeIr${}_3$ with $4f^n$ electrons where $n\le 1$-electron (Ce ion in a valence fluctuating state), both exhibit the same $s$-wave gap symmetry indicates that the physics of these two compounds is governed by the Ir-$d$ band near the Fermi-level, which is in agreement with previous band structure calculations.

8 pages 4 figures

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Cited by in corpus (10)

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• Time reversal symmetry breaking and s-wave superconductivity in CaPd2Ge2: A $\mu$SR study
• Probing the superconducting gap structure of ScRuSi via $\mu$SR and first-principles calculations
• Exploring Superconductivity in Ba${}_3$Ir${}_4$Ge${}_{16}$: Experimental and Theoretical Insights
• Nodeless time-reversal symmetry breaking in the centrosymmetric superconductor Sc${}_5$Co${}_4$Si${}_{10}$ probed by muon-spin spectroscopy
• Ferromagnetism and structural phase transition in rhombohedral PrIr3
• Multigap Superconductivity in the Filled-Skutterudite Compound LaRu${}_4$As${}_{12}$ probed by muon spin rotation
• Superconducting Gap Structure of Filled Skutterudite LaOs${}_4$As${}_{12}$ Compound through $\mu$SR Investigations
• Electronic structure of CeIr3 superconductor: DMFT studies
• Impact of the Ce $4f$ states in the electronic structure of the intermediate-valence superconductor CeIr${}_3$