Two qualitatively different superconducting phases under high pressure in single-crystalline CeNiGe${}_3$

Abstract

We have measured the temperature dependence of resistivity in single-crystalline CeNiGe${}_3$ under hydrostatic pressure in order to establish the characteristic pressure-temperature phase diagram. The transition temperature to AFM-I phase $T_{N1}$ = 5.5 K at ambient pressure initially increases with increasing pressure and has a maximum at $\sim$ 3.0 GPa. Above 2.3 GPa, a clear zero-resistivity is observed (SC-I phase) and this superconducting (SC) state coexists with AFM-I phase. The SC-I phase suddenly disappears at 3.7 GPa simultaneously with the appearance of an additional kink anomaly corresponding to the phase transition to AFM-II phase. The AFM-II phase is continuously suppressed with further increasing pressure and disappears at $\sim$ 6.5 GPa. In the narrow range near the critical pressure, an SC phase reappears (SC-II phase). A large initial slope of upper critical field ${\mu }_0{H}_{c2}$ and non-Fermi liquid behavior indicate that the SC-II phase is mediated by antiferromagnetic fluctuations. On the other hand, the robust coexistence of the SC-I phase and AFM-I phase is unusual on the contrary to superconductivity near a quantum critical point on most of heavy-fermion compounds.

5 pages, 6 figures

References in corpus (5)

• Signatures of valence fluctuations in CeCu2Si2 under high pressure
• Quantum Valence Criticality as Origin of Unconventional Critical Phenomena
• The quantum critical point in CeRhIn_5: a resistivity study
• Interacting Antiferromagnetic Droplets in Quantum Critical CeCoIn_5
• Evolution of an Unconventional Superconducting State inside the Antiferromagnetic Phase of CeNiGe${}_3$ under Pressure: a ${}^{73}$Ge-Nuclear-Quadrupole-Resonance Study

Cited by in corpus (2)

• Antiferromagnetic Order and Magnetic Frustration in the Honeycomb Heavy-Fermion System Ce(Pt${}_{1-x}$Pd${}_x$)${}_6$Al${}_3$: ${}^{27}$Al and ${}^{195}$Pt NMR Studies
• Magnetic structure and crystal field states of antiferromagnetic CeNiGe${}_3$: Neutron scattering and $\mu$SR investigations