Magnetic oxide formation at Al2O3/Co84Fe16 interface in magnetic tunnel junction

Abstract

We investigated the interfacial status of ferromagnetic Co84Fe16/insulating barrier Al2O3 of the Al2O3-based magnetic tunnel junction (MTJ) using various x-ray scattering measurements. The results show formation of orthorhombic AlFeO3 magnetic nanoparticles at the interface, which are embedded in the Al2O3 cage. Their thickness and planner size vary with the plasma oxidation time. We also observed an interesting magnetic anomaly with a minimum magnetic coercivity near the AlFeO3 ferrimagnetic T-C, which is successfully explained in terms of the AlFeO3 nanoparticles and nanoscale CoFe grains with size distribution.