Current distribution effects in patterned non-linear magnetoresistive tunnel junctions

To be used in submicronic devices like magnetic memories, magnetic tunnel j unctions require low resistances. Four-probe measurements of such resistanc es are often altered by non-uniformity of the current distribution in the j unction. The measured resistance is decreased by localised preferential con duction and increased by voltage drop in the measure electrode. Competition between these two effects is investigated as a function of the geometry. T he non-linear conduction of tunnel junctions amplifies dramatically these p henomena and can modify by more than 50% the measured resistance. (C) 2000 Elsevier Science B.V. All rights reserved.