ab-plane resistivity and possible charge stripe ordering in strongly underdoped La2-xSrxCuO4 single crystals

We have measured the ab-plane resistivity of La2−xSrxCuO4 single crystals with small Sr content (x=0.052÷0.075) between 4.2 and 300 K by using the AC Van der Pauw technique. As recently suggested by Ichikawa et al., the deviation from the linearity of the πab(T) curve starting at a temperature Tch can be interpreted as due to a progressive slowing down of the fluctuations of pre-formed charge stripes. An electronic transition of the stripes to a more ordered phase could instead be responsible for some very sharp anomalies present in the πab(T) of superconducting samples just above Tc.