We report Cu-NQR results under pressure on heavy-fermion (HF) superconductor CeCu2Si2 close to a magnetic phase, Ce 0.99Cu2.02Si2 and CeCu2(Si 0.98Ge0.02)2. It is found that an application of a minute pressure exceeding 0.3 GPa markedly suppresses low-energy magnetic fluctuations observed at ambient pressure (P = 0) in Ce0.99Cu 2.02Si2. Correspondingly, anomalous superconducting (SC) characteristics evolve into conventional HF-SC ones with increasing pressure. In the latter, the Ge substitution works as a negative chemical pressure. CeCu2(Si0.98Ge0.02)2 reveals a magnetic phase transition at TN= 0.75 K followed by the SC phase transition at Tc ∼ 0.4 K at P = 0. It is suggested experimentally that the magnetic fluctuations seen in Ce0.99Cu 2.02Si2 at P = 0 possesses a quantum critical character of both SC and magnetically ordered states.
- Heavy-fermion compounds
- Pressure effect
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics