S = 1/2 kagome lattice antiferromagnet Cu3V2O7(OH)2 · 2H2O studied by high field ESR

Abstract

X-band and high field electron spin resonance (ESR) measurements on S = 1/2 kagome lattice antiferromagnet Cu3V2O7(OH)2 · 2H2O (volborthite) have been performed. Although the kagome lattice is slightly deformed in the ab plane, no sign of magnetic order is observed down to 3.8 K, which is consistent with the magnetic susceptibility and the speciflc heat results, because the X-band ESR result shows no g-shift and the broadening of the linewidth down to 3.8 K. However, high field ESR results above 40 GHz show continuous g-shift below 20 K, which coincides with the broad maximum in the magnetic susceptibility. These results suggest the existence of the short range order and the field dependence in the system, and they are discussed in connection with the recent magnetization result.