ABOUT MECHANISM OF NEGATIVE MAGNETORESISTANCE FOR La(2)CuO(4+δ) SINGLE CRYSTAL IN THE REGIME OF MOTT INSULATOR

Abstract

We measured resistive and magnetoresistive properties of antiferromagnetic cuprate La2CuO4+δ with the Neel temperature TΝ = 265.5 K, synthesized by the method of solid phase reaction. It is shown that for this compound in the temperature range T = 20 ÷ 250 K the Mott law of variable range hopping conductivity is fulfilled. The localization length for the charge carriers is Lc = 0.4 nm. In the tem-perature range T = 17.95 ÷ 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.