On September 29, Physical Review B formally published a research paper titled "Differences in magnetic properties between the triangular-dimer-lattice antiferromagnets Rb₂Ni₂(SeO₃)₃ and K₂Co₂(SeO₃)₃" by Professor Ouyang Zhongwen's research group at the National Pulsed High Magnetic Field Science Center. 

Triangular-dimer-lattice antiferromagnets are a new class of quantum magnets composed of magnetic dimers embedded in a triangular lattice. In this study, the team successfully synthesized the novel triangular-dimer compound Rb₂Ni₂(SeO₃)₃ (spin S=1) and investigated its magnetization behavior under pulsed high magnetic fields (up to 45 T). The results reveal that Rb₂Ni₂(SeO₃)₃ undergoes long-range antiferromagnetic order at 5.8 K and exhibits a broad 1/3 magnetization plateau and a narrow 1/2 plateau along the easy *c*-axis, characteristic of an easy-axis triangular lattice antiferromagnet. Theoretical calculations further indicate that the intra-dimer exchange interaction is significantly weaker than the intra-layer exchange within the triangular lattice layers. In contrast, the isostructural S~eff~ = 1/2 compound K₂Co₂(SeO₃)₃ shows no magnetic order down to 2 K but displays distinct multiple magnetization plateaus at 1/3, 1/2, and 2/3 along the *c*-axis, exhibiting typical coupled-dimer antiferromagnetic behavior. Thus, the two structurally similar but spin-different compounds exhibit markedly different magnetic properties and plateau behaviors, highlighting the complexity of the competition between the dimer and triangular lattice interactions. This research provides a new experimental platform for understanding quantum effects in triangular-dimer-lattice antiferromagnets.

High magnetic field magnetization curves: a, b for Rb₂Ni₂(SeO₃)₃; c, d for K₂Co₂(SeO₃)₃.

Paper link: https://journals.aps.org/prb/abstract/10.1103/6csj-22vw