Effect of scattering at lateral edges on the current-perpendicular-to plane giant magnetoresistance of submicronic pillars

From a phenomenological point of view, we have investigated the effect of scattering at lateral edges on the current-perpendicular-to-plane (CPP) transport properties of submicronic magnetic multilayer pillars. This scattering can be considered as a current-in-plane contribution in the CPP geometry. As a first attempt to calculate the CPP resistance and GMR in this situation, we have combined the serial resistance network model of CPP transport with an exponential variation of the local conductivity as a function of the distance from the edges of the pillars assuming that the scattering is perfectly diffusive at the edges of the pillars. As the lateral size of the pillars decreases below 100 nm, it is shown that this scattering leads to a strong increase in the CPP resistivity as well as a decrease in both DeltaR/R and DeltaR* area. Furthermore, due to the difference in mean-free paths from layer to layer, the current lines are no longer uniform in the pillar even if the latter is the shape of an infinite cylinder. (C) 2001 American Institute of Physics.