Temperature and Ag Doping Effect on Magnetic Excitations in the Quasi-Two-Dimensional Triangular Lattice Antiferromagnet CuCrO2 Studied by Inelastic Neutron Scattering

We have studied magnetic excitations in quasi-two-dimensional triangular lattice antiferromagnets CuCrO2 and Cu0.85Ag0.15CrO2 by inelastic neutron scattering. CuCrO2 has two types of magnetic excitations: one is highly dispersive, while the other is less dispersive and spreads over a wide Q range. With increasing temperature, the weight of the latter component transfers to a lower energy, and the spin dynamics becomes a mixture of a disordered spin wave and another diffuse component. Ag doping induces a similar spin dynamics even at 5 K. This manifests the impact of Ag doping on magnetic correlations and gives a clue to understanding the unconventional spin state in the Ag-doped CuCrO2.