  We report results of 51V NMR in the field-induced phase of volborthite
Cu3V2O7(OH)dot2H2O, a spin-1/2 antiferromagnet on a distorted kagome lattice.
In magnetic fields above 4.5 T, two types of V sites with different spin-echo
decay rates are observed. The hyperfine field at the fast decaying sites has a
distribution, while it is more homogeneous at the slowly decaying sites. Our
results indicate a heterogeneous state consisting of two spatially alternating
Cu spin systems, one of which exhibits anomalous spin fluctuations contrasting
with the other showing a conventional static order.
