Quantum critical spin-liquid-like behavior in S = 1/2 quasi-kagome lattice compound CeRh₁-ₓPdₓSn investigated using muon spin relaxation and neutron scattering

We present the results of muon spin relaxation (μSR) and neutron scattering on the Ce-based quasikagome lattice CeRh1−xPdxSn (x=0.1 to 0.75). Our ZF-μSR results reveal the absence of static long-range magnetic order down to 0.05~K in x=0.1 single crystals. The weak temperature-dependent plateaus of the dynamic spin fluctuations below 0.2~K in ZF-μSR together with its longitudinal-field (LF) dependence between 0 and 3~kG indicate the presence of dynamic spin fluctuations persisting even at T = 0.05~K without static magnetic order. On the other hand, C4f/T increases as --log T on cooling below 0.9~K, passes through a broad maximum at 0.13~K and slightly decreases on further cooling. The ac-susceptibility also exhibits a frequency independent broad peak at 0.16~K, which is prominent with an applied field H along c-direction. We, therefore, argue that such a behavior for x=0.1 (namely, a plateau in spin relaxation rate (λ) below 0.2~K and a linear T dependence in C4f below 0.13~K) can be attributed to a metallic spin-liquid (SL) ground state near the quantum critical point in the frustrated Kondo lattice. The LF-μSR study suggests that the out of kagome plane spin fluctuations are responsible for the SL behavior. Low energy inelastic neutron scattering (INS) of x = 0.1 reveals gapless magnetic excitations, which are also supported by the behavior of C4f proportional to T1.1 down to 0.06~K