Magnetic excitations affected by spin-lattice coupling in the <i>S</i>=3/2 triangular lattice antiferromagnet Ag₂CrO₂

Ag₂CrO₂ is an S=3/2 triangular lattice antiferromagnet in which long-range magnetic order with a 5-fold magnetic unit cell appears below the transition temperature (T_N) of 24 K [1]. The long range magnetic order is accompanied by a structural transition. Inelastic neutron scattering experiments were performed to investigate the magnetic interactions, anisotropy, and correlations in this material. Above T_N, diffuse scattering originating from the short-ranged magnetic correlations consistent with a 120-degree structure was observed. The magnetic excitations below T_N were reproduced reasonably well using a linear spin-wave model with further-neighbor interactions and easy-axis anisotropy, which are predicted to be due to a previously proposed spin-lattice coupling [2].
[1] M. Matsuda et al., Phys. Rev. B 85, 144407 (2012).
[2] F. Wang and A. Vishwanath, Phys. Rev. Lett. 100, 077201 (2008).