Dimensional crossover from anisotropic-three-dimensional (3D) to 2D low-energy magnetic excitations was found in delafossite oxide Cu 1-xAgxCrO2 having a spin-3/2 antiferromagnetic (AF) triangular lattice. The crossover is evidenced by a decrease in AF transition temperature (TN), distinct 2D magnetic excitations above TN for Cu0.85Ag0.15CrO2, a disappearance of a peak of magnetic specific heat (Cmag) around TN, and a successive change from T3 to T2 dependence of low-T Cmag accompanying a low-T shift of magnetic entropy. These results may suggest a gradual change from AF to spin-liquid like states with an increase in x.
- Antiferromagnetic triangular lattice
- Magnetic frustration