CHARGE DENSITY WAVE TRANSPORT IN THE BLUE BRONZES K_<0.30>MoO_3 AND Rb_<0.30>MoO_3(EXPERIMENTS ON BLUE BORNZES, International Symposium on NONLINEAR TRANSPORT AND RELATED PHENOMENA IN INORGANIC QUASI ONE DIMENSIONAL CONDUCTORS)

Abstract

We report data on non linear conductivity and both slow and fast voltage oscillations in the blue bronzes K_<0.30>MoO_3 and RbK_<0.30>MoO_3. These properties are attributed to the depinning of the CDW. The data obtained on Rb_<0.30>MoO_3 are very similar to those obtained previously on K_<0.30>MoO_3. We have studied in details the slow phenomena, time dependent effects voltage pulses or coherent oscillations both in "pure" and doped K_<0.30>MoO_3. While pulses are found in the "pure" samples, the doped ones rather show oscillations, more or less coherent depending on the cooling process with or without a dc current. We propose that the slow phenomena are related to the CDW domain boundaries,discommensurations or dislocations in the CDW lattice. We suggest that possible diffusion of defects, possibly impurities, coupled either with the CDW modulation or with the domain boundaries, may account for the time dependent and memory effects.