This work describes the study on the magnetization reversal for two different spin valves: the first one is characterized by in-plane magnetic anisotropy, and the second by a perpendicular anisotropy. Magnetoresistance-first-order-reversal-curve analysis was used in order to map the magnetoresistance of each valve as a function of the coercive fields and the interaction fields of the particles in the layers. For the valve with in-plane anisotropy, it was possible to identify an exchange-spring behavior in the pinned layer induced by the contact with the AF layer, and mean-field effects produced by interparticle interactions. Also, it was determined that the rotation of the magnetization of the pinned layer cannot happen by coherent rotation. For the second valve, it was possible to identify the distribution of coercivities and interaction fields of each layer, as a function the different magnetic orientations that they may have. [ABSTRACT FROM AUTHOR]