Observation of giant magnetoresistance in CoFeN/AlOx/CoFeN magnetic tunneling junctions employing a nitrogen-doped amorphous CoFeN free layer electrode

Abstract

We examine the crystallographic and magnetic features of nitrogen-doped amorphous CoFe (CoFeN) electrodes for application as ferromagnetic free layers in magnetic tunnel junctions, in which precise control of the nitrogen content is crucial for achieving the desirable magnetic features. Incorporating nitrogen into the CoFe layer during growth provides numerous benefits including a remarkably reduced coercivity of 5 Oe, a phase transition from polycrystalline to amorphous, a low magnetization of 294 emu/cm(3), and an enhanced thermal stability up to 400 degrees C. A high magnetic resistance ratio of about 220% was also obtained for annealed in-plane CoFeN/AlOx/CoFeN magnetic tunneling junctions containing a 1.2-nm-thick amorphous AlOx tunnel barrier. We anticipate that our experimental findings will aid in the development of a variety of future spintronic devices.