ABOUT MECHANISM OF NEGATIVE MAGNETORESISTANCE FOR La2CuO4+delta SINGLE CRYSTAL IN THE REGIME OF MOTT INSULATOR

We measured resistive and magnetoresistive properties of antiferromagnetic cuprate La2CuO4+delta with the Neel temperature T-N = 265.5 K, synthesized by the method of solid phase reaction. It is shown that for this compound in the temperature range T = 20 divided by 250 K the Mott law of variable range hopping conductivity is fulfilled. The localization length for the charge carriers is L-c = 0.4 nm. In the temperature range T = 17.95 divided by 99.93 K in magnetic fields up to 1.75 T a quadratic with field negative magnetoresistance was discovered. We suggest that the known interference model of negative magnetoresistance in which the magnetic field influences the localized electron spins can be used to explain the found magnetoresistive effects.