Perpendicular giant magnetoresistance in spin valves

We investigated the angular dependence of the conductance and giant magnetoresistance in the current perpendicular-to-the-plane geometry in magnetic spin valves via a third-nearest-neighbor tight-binding model with s, p, and d orbitals. An iterative method is used to calculate the Green's function of the spin valve. The conductance, due to both minority and majority spin channels, is calculated for arbitrary angles between the magnetizations of the magnetic layers using the Landauer-B\"uttiker formula. We found that the leading contribution to the conductance is proportional to cosφ, where φ is the angle between the magnetizations of the magnetic layers. The slope of the conductance vs cosφ is proportional to the spin splitting of the band structure of the magnetic materials.