Ferromagnetic tunnel junctions with high thermal stability

Abstract The junctions exposed to pure oxygen at the interface between the bottom CoFe layer and Al-oxide insulator were prepared. The junctions showed high thermal stability of tunnel magnetoresistance (TMR) ratio up to 375°C in comparison with the standard junction oxidized with plasma. Auger electron spectroscopy (AES) profiles revealed that the Mn diffusion occurred even for the junction with high thermal stability after annealing over 375°C. A large amount of oxygen existing at the interface might oxidize the Mn diffusing at the interface.