Current-perpendicular (CPP) magnetoresistance in magnetic metallic multilayers

We present an experimentalist's view of the theory and published data for the magnetoresistance (MR) of a multilayer composed of alternating ferromagnetic (F) and non-magnetic (N) metals measured with current Row perpendicular to the layer planes (CPP-MR). We explain the advantages of this geometry for determining the fundamental quantities underlying spin-polarized transport, describe the different techniques developed to measure the CPP-MR, summarize the salient features of the models used to analyze experimental data, and describe tests of those models. We then review what has been learned so far about spin-dependent scattering anisotropy and spin relaxation in F-metals and at F/N interfaces, specific resistances of F/N interfaces, the temperature dependence of spin-polarized transport parameters, and mixing of the spin-polarized electron currents. After a brief overview of some new directions, we conclude with a list of questions still to be answered, (C) 1999 Elsevier Science B.V. All rights reserved.