  The resistivity of disordered metallic layer sandwiched by two ferromagnetic
layers at low-temperature is investigated theoretically. It is shown that the
magnetic field acting at the interface does not affect the classical Boltzmann
resistivity but causes a dephasing among electrons in the presence of the
spin-orbit interaction, suppressing the anti-localization due to the spin-orbit
interaction. The dephasing turns out to be stronger in the case where the
magnetization of the two layers is parallel, contributing to a positive
magnetoresistance close to a switching field at low temperature.
