Anomalous Spin Dynamics Observed by High-Frequency ESR in Honeycomb Lattice Antiferromagnet InCu2/3V1/3O3

Publisher Website
Google Scholar
Abstract
High-frequency ESR results on the S =1/2 Heisenberg hexagonal antiferromagnet InCu 2/3 V 1/3 O 3 are reported. This compound appears to be a rare model substance for the honeycomb lattice antiferromagnet with very weak interlayer couplings. The high-temperature magnetic susceptibility can be interpreted by the S =1/2 honeycomb lattice antiferromagnet, and it shows a magnetic-order-like anomaly at T N =38 K. Although, the resonance field of our high-frequency ESR shows the typical behavior of the antiferromagnetic resonance, the linewidth of our high-frequency ESR continues to increase below T N , while it tends to decrease as the temperature in a conventional three-dimensional antiferromagnet decreases. In general, a honeycomb lattice antiferromagnet is expected to show a simple antiferromagnetic order similar to that of a square lattice antiferromagnet theoretically because both antiferromagnets are bipartite lattices. However, we suggest that the observed anomalous spin dynamics below T N is the peculiar feature of the honeycomb lattice antiferromagnet that is not observed in the square lattice antiferromagnet.