Coexistence of local magnetism and superconductivity in the heavy-fermion CeRh${}_2$As${}_2$ revealed by $\mu$SR studies

Abstract

The superconducting (SC) state ($T_{\mathrm{c}}$ = 0.3 K) of the heavy-fermion compound CeRh${}_2$As${}_2$, which undergoes an unusual field-induced transition to another high-field SC state, emerges from an unknown ordered state below $T_{\mathrm{o}}$ = 0.55 K. While an electronic multipolar order of itinerant Ce-4$f$ states was proposed to account for the $T_{\mathrm{o}}$ phase, the exact order parameter has not been known to date. Here, we report on muon spin relaxation ($\mu$SR) studies of the magnetic and SC properties in CeRh${}_2$As${}_2$ single crystals at low temperatures. We reveal a magnetic origin of the $T_{\mathrm{o}}$ order by identifying a spontaneous internal field below $T_{\mathrm{o}}$ = 0.55 K. Furthermore, we find evidence of a microscopic coexistence of local magnetism with bulk superconductivity. Our findings open the possibility that the $T_{\mathrm{o}}$ phase involves both dipole and higher order Ce-4$f$ moment degrees of freedom and accounts for the unusual non-Fermi liquid behavior.

7 pages, 4 figures, and supplemental material

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Cited by in corpus (12)

• Unified picture of superconductivity and magnetism in CeRh${}_2$As${}_2$
• Inversion-asymmetric itinerant antiferromagnets by the space group symmetry
• The phase diagram of CeRh${}_2$As${}_2$ for out-of-plane magnetic field
• Thermodynamics, elastic anomalies and excitations in the field induced phases of CeRh2As2
• Incommensuration in odd-parity antiferromagnets
• Conventional $s$-wave Superconductivity in LaRh${}_2$As${}_2$; the Analog without the 4$f$ Electrons of CeRh${}_2$As${}_2$
• Unveiling the superconducting scenario in multiphase superconductor CeRh${}_2$As${}_2$ from space-group symmetry analysis and DFT calculations
• Coulomb blockade thermometry based nanocalorimetry
• Composite Superconducting Orders and Magnetism in CeRh${}_2$As${}_2$
• Quasiclassical theory of vortex states in locally non-centrosymmetric superconductors: application to CeRh${}_2$As${}_2$
• La substitution studies on the heavy-fermion superconductor CeRh${}_2$As${}_2$
• Multipolar fluctuations from localized 4f electrons in CeRh2As2