High-field and multi-frequency ESR in the quasi two-dimensional triangular-lattice antiferromagnet CuCrO ₂

We have performed high-field and multi-frequency electron spin resonance (ESR) and magnetization measurements in magnetic fields up to about 53 T on single crystals of a delafossite triangular-lattice antiferromagnet CuCrO ₂, which has been proposed to show an out-of-plane 120° spiral spin structure below about 24 K. We calculated ESR resonance modes and magnetization curves assuming an Ising-like Heisenberg Hamiltonian with a spiral spin structure by a mean-field theory. The experimental results can be well reproduced using the following parameters, the intralayer exchange constant J/k _B=26.9 K, the easy-axis anisotropy D/k _B=-0.47 K, and the in-plane g-factor g _ab =2.0.