Abstract
The annealing temperature dependence of the tunnel magnetoresistance (TMR) ratio for ferromagnetic tunnel junctions with CoFeOx inserted in the pinned layer was investigated. A junction with a CoFe/CoFeOx/CoFe as the pinned layer exhibited TMR ratios of 47 % and 43 % after annealing at 350°C and at 375°C respectively, The reason for the improvement of the thermal stability is related to oxygen diffusion from CoFeOx layer, and there is a possibility that CoFeOx plays a role of Mn (in MnIr exchange layer) diffusion barrier.
