Quantum-well resistivity for perpendicular transport in magnetic layered systems

We show that quantum-well states enhance the current-perpendicular-to-plane s resistivity of a metal film compared to the resistivity in the bulk at fi lm thicknesses comparable with the mean free path due to the reduced number of conducting channels within the potential-well structure. This makes the mean free path an important parameter, which must be taken into account fo r the accurate treatment of results on current-perpendicular-to-plane giant magnetoresistance, rather than ignored by applying the two-current series- resistor model.