Quasi-1D XY antiferromagnet Sr(2)Ni(SeO(3))(2)Cl(2) at Sakai-Takahashi phase diagram

Uniform quasi-one-dimensional integer spin compounds are of interest as a potential realization of the Haldane conjecture of a gapped spin liquid. This phase, however, has to compete with magnetic anisotropy and long-range ordered phases, the implementation of which depends on the ratio of interchain J′ and intrachain J exchange interactions and both uniaxial D and rhombic E single-ion anisotropies. Strontium nickel selenite chloride, Sr(2)Ni(SeO(3))(2)Cl(2), is a spin-1 chain system which passes through a correlations regime at T(max) ~ 12 K to long-range order at T(N) = 6 K. Under external magnetic field it experiences the sequence of spin-flop at B(c1) = 9.0 T and spin-flip transitions B(c2) = 23.7 T prior to full saturation at B(sat) = 31.0 T. Density functional theory provides values of the main exchange interactions and uniaxial anisotropy which corroborate the experimental findings. The values of J′/J = 0.083 and D/J = 0.357 place this compound into a hitherto unoccupied sector of the Sakai-Takahashi phase diagram.