The static and dynamic magnetic properties of an S = 1/2 stacked triangular antiferromagnet RbCuCl3 with a helical spin structure due to lattice distortion were investigated by magnetic susceptibility, high-field magnetization process and ESR measurements. The magnetic susceptibilities were analyzed by high-temperature expansion approximation in terms of ferromagnetic intrachain coupling and the antiferromagnetic interchain coupling. The magnetization saturates at Hs ≈ 66.8 T at 1.5 K, the value of which is twice that of CsCuCl3. A small magnetization jump indicative of a phase transition was observed at Hc = 21.2 T ≈ (1/3)Hs for H ⊥ c. ESR modes observed for H ∥ c are well described by the calculation based on the helical spin structure. From the present measurements, the ferromagnetic intrachain and two kinds of antiferromagnetic interchain exchange interactions, and the planar anisotropy energy were determined as J0/kB = 25.7 K, J1/kB = -10.6 K, J′1/kB = -17.4 K, and ΔJ0/kB = -0.45 K, respectively.
- Distorted triangular antiferromagnet
- Field-induced phase transition
- Helical spin structure
- High-field magnetization process