The free layer reversal of spin valves studies by planar Hall effect

Abstract

Summary form only given. It is well established that anisotropic magnetoresistance (AMR) can be used as a probe of magnetization reversal and domain structure in small-size systems. The planar Hall effect (PHE) originates purely from the AMR effect and only depends on the angle between the magnetization and the direction of sensing current. The authors focus on the PHE behavior in spin valves with the structure Si[100]/Ta/NiFe/Cu/NiFe/FeMn/Ta prepared in a sputtering system. MR(H) and PHE(H) curves of spin-valves were simultaneously measured in fields applied in the film plane at different angles /spl alpha/ with respect to the easy axis of the free layer. Besides the usual PHE behavior, they observed an unusual upward and downward jump in PHE voltage, superimposed on the normal curves at the switching field. Results showed that this anomalous jump in PHE voltage originated from Neel domain effects. Furthermore, the information about magnetization reversal can be derived from simulated PHE curves.