Synthesis and characterization of a two-dimensional antiferromagnet KNiB4O6F3 with triangular spin lattice

We prepared a layered antiferromagnet KNiB 4 O 6 F 3 1 by hydrothermal synthesis, and characterized its structure and physical properties by X-ray diffraction, magnetization and specific heat measurements as well as thermal stability, FTIR and UV–vis–NIR measurements. 1 consists of layers of composition [NiB 4 O 6 F 3 ] - separated by layers of K + cations. And Ni 2+ ions are arranged in slightly distorted triangular pattern in each [NiB 4 O 6 F 3 ] - layer. The magnetic susceptibility measurements indicate no divergence between the zero-field-cooled and field-cooled curves down to 7.9 K, below which a long-range order takes place as verified by specific heat measurements. The M ( H ) curve linearly increases when the field is weak (below ∼2 T), confirming that the ground state of 1 is antiferromagnetic. At 7 T, the magnetization of 1 is 1.67 μ B which is lower than the saturation magnetization.