Exotic superconductivity in the coexistent phase of antiferromagnetism and superconductivity in CeCu2(Si0.98Ge0.02)2: A Cu-NQR study under hydrostatic pressure

Abstract

We report a pressure ($P$) effect on CeCu${}_2$(Si${}_{0.98}$Ge${}_{0.02}$)${}_2$ where an antiferromagnetic (AFM) order at $T_N\sim$ 0.75 K coexists with superconductivity below $T_c\sim$ 0.4 K\@. At pressures exceeding $P=0.19$ GPa, the AFM order is suppressed, which demonstrates that the sudden emergence of AFM order due to the Ge doping is ascribed to the intrinsic lattice expansion. The exotic superconductivity at $P=0$ GPa is found to evolve into a typical heavy-fermion one with a line-node gap above $P=0.91$ GPa\@. We highlight that the anomalous enhancement in nuclear spin-lattice relaxation rate $1/T_1$ that follows a $T_{1}T$ = const. behavior well below $T_c$ at $P$ = 0 GPa is characterized by the persistence of low-lying magnetic excitations, which may be inherent to the coexistent state of antiferromagnetism and superconductivity.

arXiv comment5 pages with 4 figures embedded in the text. To be published in J. Phys. Soc. Jpn

References in corpus (3)

• Pressure-induced anomalous magnetism and unconventional superconductivity in CeRhIn5 : 115In-NQR Study under Pressure
• Exotic Superconducting Phase in CeCu2Si2 Close to Antiferromagnetism : A Cu-NQR Study under Hydrostatic Pressure
• ^{115}In-NQR evidence for unconventional superconductivity in CeIn_3 under pressure

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