Spin dynamics of the one-dimensional double chain spin- 12 antiferromagnet KNaCuP2 O7

Abstract

© 2022 American Physical Society.We combine a muon spin relaxation (μSR) technique with thermodynamic measurements to explore the spin dynamics of one-dimensional (1D) S=12 antiferromagnetic double chain KNaCuP2O7. Static magnetic susceptibility and specific heat are well described by a uniform 1D spin chain model with the intrachain interaction J/kB≈55K and small interchain interactions. Spin excitations probed by zero-field μSR evince that high-temperature diffusive spin transport turns into ballistic behavior with decreasing temperature below 30 K. In addition, we observe that longitudinal-field μSR varies hardly with an external magnetic field. The field-independent dynamical spin susceptibility disagrees with diffusive or ballistic behaviors.