Effect of impurities on the anomalous transport properties of NbSe3

Studies on the effect of charged (Ti) and uncharaged (Ta) impurities on the non-Ohmic behavior of and microwave absorption in NbSe3 show that (1) the characteristic field E0 increases as c2 (c=Ta concentration), in agreement with a recent calculation by Lee and Rice; (2) the microwave absorption is suppressed by impurities; and (3) charged impurities are strikingly more effective in supressing the anomalous properties. These conclusions provide very strong evidence for Fröhlich sliding-mode conductivity in the nominally pure compound.