Pressure-induced antiferromagnetic superconductivity in CeNiGe3:: A 73Ge-NQR study under pressure

We report on antiferromagnetic (AF) properties of pressure-induced superconductivity in CeNiGe3 via the Ge-73 nuclear-quadrupole-resonance (NQR) measurements under pressure (P). The NQR-spectrum measurements have revealed that the incommensurate antiferromagnetic ordering is robust against increasing P with the increase of ordered moment and ordering temperature. Nevertheless the measurements of nuclear spin-lattice relaxation rate (1/T-1) have pointed to the onset of superconductivity as a consequence of Ce-4f electrons delocalized by applying P. The emergence of superconductivity under the development of AF order suggests that a novel type of superconducting mechanism works in this compound. (c) 2006 Elsevier B. V. All rights reserved.