CoFeB Magnetic Tunnel Junctions (original) (raw)

Magnetic tunnel junctions (MTJs) with the core structure of CoFeB MgAlO x CoFeB were fabricated using magnetron sputtering technique. The MgAlO x tunnel barrier was obtained by plasma oxidation of an Mg/Al bilayer in an Ar + O 2 atmosphere. Series of MTJs were fabricated with different Mg layer thicknesses ( Mg ), and Al layer thickness was fixed at 1.3 nm. The annealing effect on the tunneling magnetoresistance (TMR) ratio was investigated, and TMR ratio of 65% at room temperature (RT) was shown when it was annealed at 375 C with the Mg = 0 5 nm. The temperature dependence of conductance can be fit by the magnon-assisted tunneling model by adding spin independent tunneling contribution for the samples investigated here, and the spin independent conductance varies with Mg , possibly due to less oxidation for thicker Mg layer.