Low-temperature resistance noise in lightly doped La_(2-x)Sr_x CuO_4

摘要

Studies of low-frequency noise in the c-axis resistance of lightly doped La_(2-x)Sr_x CuO_4 (x = 0.03) have revealed distinct switching fluctuations at low temperatures and in magnetic fields B of up to 9 T parallel to the c-axis of the crystal. The switching noise is modulated by some slower events and becomes less prominent with increasing temperature T. Our results demonstrate the existence of multiple metastable states in the presence of B. The overall behavior of the noise is consistent with the picture of microscopic segregation of doped holes into hole-rich regions separated by undoped domains in CuO_2 planes. It also strongly suggests that interactions should be included in possible theoretical models to describe the data.