Antiferromagnetic correlations and the normal-state transport in heavily underdoped YBa2Cu3O6+x

The Neel ordering in heavily underdoped YBa2Cu3O6+x has remarkably differen t impact on the electron transport within CuO2 planes and between them. Whi le the in-plane resistivity and magnetoresistance (MR) are smooth through t he Neel temperature T-N, the out-of-plane transport demonstrate striking an omalies, e.g. the MR increases by two orders of magnitude at T-N. These obs ervations give evidence that the spin fluctuations play the key role in the out-of-plane transport and that the charge confinement within the CuO2 pla nes is related to the spin degrees of freedom. We discuss whether the pictu re of charged stripes can account for these features.