Muon spin rotation study to investigate a possible quantum spin liquid behaviour in 1D spin-chain compound K2NdNb5O15

K2RENb5O15 (RE = rare earths), which form in tetragonal tungsten-bronze structure, display interesting magnetic properties arising from 1D linear spin-chain of RE3+ ions along the c-axis. The magnetic susceptibility measurements show absence of long-range magnetic ordering in K2NdNb5O15 down to 1.8 K. The fit to high temperature susceptibility gives Curie-Weiss temperature of p =-70.3 K for K2NdNb5O15. However, at low temperature susceptibility reveals p =-0.87 K indicating a weak AFM correlations. Our heat capacity measurements in zero-field down to 50 mK of K2NdNb5O15 reveal a broad peak at 0.4 K, while the peak moves to 1.5 K in applied field of 3 T, suggesting ferromagnetic correlations. The ac susceptibility also shows a corresponding anomaly. Our inelastic neutron scattering study on K2NdNb5O15 on MARI reveals well defined four crystal field excitations indicating the localized nature of the Nd magnetism with a possible Jeff=1/2 ground state. It would be interesting to investigate the nature of the ground state of K2NdNb5O15 using microscopic and sensitive technique, such as muon spin rotation and relaxation to investigate a possible quantum spin liquid behavior in this 1D Nd-spin-chain. The muon study will give directly confirm of the presence or absence of long range magnetic ordering of Nd-moment and throw light on a possible quantum spin liquid ground state.