Current-induced magnetic switching in nanopillar spin-valve systems with double free layers

Abstract

Double soft ferromagnetic layers-CoFe/Pd/CoFe-were employed as a free layer of nanopillar spin valve. The system showed double jumps in electric resistance with respect to the spin current. Each jump corresponds to the switching of one of the CoFe layers in the double free layer. The absolute change in resistance of each jump is the same in the resistance versus current scans taken at different applied field values. While both jumps are present only in larger fields, only one jump is observed in low fields, which is attributed to the reversal of the inner CoFe layer. Furthermore, in the latter case an inversion of the hysteresis has been observed, which is explained by telegraph noise.