Absence of weak localization effects in strongly underdoped La2-xSrxCuO4

Recent studies of the magnetoresistance (MR) of strongly underdoped La2-xSrxCuO4 with 0.03 < x < 0.05 are discussed. The analysis of the MR measured in magnetic fields up to 14 T, parallel and perpendicular to the CuO2 plane, indicate predominant role of interactions and the absence of weak localization effects. A positive orbital MR is observed close to the boundary between the spin-glass and the antiferromagnetic phase, suggesting the presence of the Maki-Thompson superconducting fluctuations deep inside the insulating phase