L1(0) ordering of FePtB layers by oxidation-induced stress of capping layer

Abstract

We have studied the L1(0) ordering of FePtB layers assisted by the oxidation-induced stress of a capping layer. In the thermally oxidized Si substrate/MgO/CoFeB/FePtB/ Ti structure, the oxidation of the Ti capping layer during post-deposition annealing exerts an in-plane tensile stress on the FePtB layer, which promotes L1(0) ordering of the FePtB layer. The diffusion of boron from the FePtB layer into the Ti layer also plays a crucial role in the L1(0) ordering. The CoFeB/FePtB composite layers can be used for the top electrode of perpendicular magnetic tunnel junctions.