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 s cattering at lateral edges on the current-perpendicular-to-plane (CPP) tran sport properties of submicronic magnetic multilayer pillars. This scatterin g 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 situati on, we have combined the serial resistance network model of CPP transport w ith an exponential variation of the local conductivity as a function of the distance from the edges of the pillars assuming that the scattering is per fectly diffusive at the edges of the pillars. As the lateral size of the pi llars decreases below 100 nm, it is shown that this scattering leads to a s trong 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 f rom layer to layer, the current lines are no longer uniform in the pillar e ven if the latter is the shape of an infinite cylinder. (C) 2001 American I nstitute of Physics.