Data for Single-ion anisotropy driven chiral magnetic order in a spin-1 antiferromagnetic chain

Herein, we present a comprehensive experimental study of a chiral antiferromagnetic S = 1 chain, [Ni(pym)(H2O)4]SO4· H2O (pym = pyrimidine), where the Ni(II) octahedral orientation exhibits a four-fold chiral periodicity. Muon spin rotation measurements indicate the onset of long-range magnetic order below TN = 1.82(2) K. Neutron diffraction measurements reveal a chiral antiferromagnetic order driven by a chiral modulation of the easy axis anisotropy direction, rather than the typical scenario of Dzyaloshinskii-Moriya interactions, geometrical frustration or higher-order interactions.

Inelastic neutron scattering measurements reveal dispersive spin-wave excitations well described by linear spin-wave theory, with Hamiltonian parameters J0 = 6.81(1) K (intrachain exchange), J′1a = −0.09(1) K (interchain exchange), and D = −3.02(1) K (easy-axis single-ion anisotropy). These parameters are further validated by Monte Carlo simulations of the magnetisation. Additionally, the inelastic neutron scattering data reveal multiple dispersionless bands, suggesting the presence of further excitations beyond the scope of our linear spin-wave theory.<br><br>Data accompanying "Single-ion anisotropy driven chiral magnetism in a Spin-1 antiferromagnetic chain" Phys.