Nuclear quadrupole resonance and nuclear magnetic resonance studies of heavy fermion Ce1−xRxRhIn5 (R=Y,La)

The results of 115In nuclear quadrupole resonance (NQR) measurements on Ce1−xYxRhIn5 and Ce1−xLaxRhIn5 are reported. The observed NQR frequency at an In(1) site varies linearly with lattice parameter and dopant concentration for Y- and La-substituted systems. For the samples of LaMIn5 (M=Co,Rh,Ir) and YRhIn5, T1−1’s are proportional to the temperature, which means the system is in the Fermi liquid state in a wide temperature range. On the other hand, in Ce0.1La0.9RhIn5 and Ce0.5Y0.5RhIn5, T1−1’s have power-law temperature dependences (close to T1/4), which are expected to be from non-Fermi-liquid behavior near a quantum critical point. For Ce0.5La0.5RhIn5 and Ce0.25La0.75RhIn5, T1−1’s stay temperature independent below 4.2 K and the observed linewidths of 115In become broader with decreasing temperature. This behavior may be associated with a short-range magnetic order of Ce expected from the macroscopic measurements.