Magnetism and ESR of the Seff= 12 antiferromagnet BaCo2(SeO3)3·3 H2 O with dimer-chain structure

We report the magnetism and ESR of the Seff=1/2 compound BaCo2(SeO3)3·3H2O with dimer-chain structure. The magnetic susceptibility and heat capacity show that the compound is antiferromagnetically ordered at TN=7.6 K. The magnetization M(H) curve at 2 K presents a spin-flop transition within 2.6-3.0 T when the magnetic field is applied along the ab plane (H⊥c), pointing to the easy axis-like anisotropy. In high magnetic field, the magnetization increases nearly linearly until saturation at about 22 T, indicating a classical-like behavior. The magnetization process can be described with the intradimer exchange J1=-20.0 K and interdimer exchanges J2=-14.6 K and J3=-6.2 K. Thus, BaCo2(SeO3)3·3H2O is approximately a three-dimensional antiferromagnet, although structurally it contains dimer chains. © 2022 American Physical Society.