Spin dynamics of edge-sharing spin chains in SrCa13Cu24O41

The low-energy magnetic excitation from the highly Ca-doped quasi-one-dimensional magnet SrCa13Cu24O41 was studied in the magnetic ordered state by using inelastic neutron scattering. We observed the gapless spin-wave excitation, dispersive along the a and c axes but nondispersive along the b axis. Such excitations are attributed to the spin wave from the spin-chain sublattice. Model fitting to the experimental data gives the nearest-neighbor interaction Jc as 5.4 meV and the interchain interaction Ja=4.4meV. Jc is antiferromagnetic and its value is close to the nearest-neighbor interactions of the similar edge-sharing spin-chain systems such as CuGeO3. Comparing with the hole-doped spin chains in Sr14Cu24O41, which shows a spin gap due to spin dimers formed around Zhang-Rice singlets, the chains in SrCa13Cu24 O41 show a gapless excitation in this paper. We ascribe such a change from gapped to gapless excitations to holes transferring away from the chain sublattice into the ladder sublattice upon Ca doping. ©2018 American Physical Society

Keywords

Exchange interactions, Spin, Magnetism, Antiferromagnetism, Excitation, Inelastic scattering

Citation

Deng, G., Yu, D., Mole, R., Pomjakushina, E., Conder, K., Kenzelmann, M., Yano, S.-I., Wang, C.-W., Rule, K. C., Gardner, J. S., Luo, H., Li, S., Ulrich, C., Imperia, P., Ren, W., Cao, S., & McIntyre, G. J. (2018). Spin dynamics of edge-sharing spin chains in SrCa13Cu24O41. Physical Review B, 98(18), 184411. doi:10.1103/PhysRevB.98.184411