Rule, K.; Willenberg, B.; Schäpers, M.; Wolter, A.; Büchner, B.; Drechsler, S.; Ehlers, G.; Tennant, D.; Mole, R.; Gardner, J.; Süllow, S.; Nishimoto, S.: Dynamics of linarite: Observations of magnetic excitations. Physical Review B 95 (2017), p. 024430/1-6
10.1103/PhysRevB.95.024430

Abstract:
Here we present inelastic neutron scattering measurements from the frustrated, quantum spin-1/2 chain material linarite, PbCuSO4(OH)2. Time of flight data, taken at 0.5 K and zero applied magnetic field reveals low-energy dispersive spin wave excitations below 1.5 meV both parallel and perpendicular to the Cu-chain direction. From this we confirm that the interchain couplings within linarite are around 10% of the nearest neighbor intrachain interactions. We analyze the data within both linear spin-wave theory and density matrix renormalization group theories and establish the main magnetic exchange interactions and the simplest realistic Hamiltonian for this material.