Dual magnetic correlations in filled skutterudite compound NdRu4P12

We report the results of P-31-nuclear magnetic resonance, Ru-101-nuclear quadrupole resonance (NQR), and ac susceptibility (chi(ac)) measurements on NdRu4P12. This compound is one of the filled skutterudite family RRu4P12 (R = rare earth) in which intimate relationships between 4f and conduction electrons with the nesting property of the Fermi surface may play an important role in a variety of intriguing low-temperature states. The NQR and chi(ac) measurements indicate the appearance of ferromagnetic ordering below T-C = 1.7 K. In the paramagnetic state, the coexistence of ferromagnetic and antiferro-type spin correlations are suggested from the field and temperature dependences of the Knight shift and the spin-lattice relaxation time. Such dual spin fluctuations can be explained by considering contributions from both localized 4f and conduction electrons with the nesting condition.