Properties of magnetic tunnel junctions with a MgO/CoFeB/Ta/CoFeB/MgO recording structure down to junction diameter of 11 nm

We investigate properties of perpendicular anisotropy magnetic tunnel junctions (MTJs) with a recording structure of MgO/CoFeB/Ta/CoFeB/MgO down to junction diameter (D) of 11 nm from 56 nm. Thermal stability factor (Delta) of MTJ with the structure starts to decrease at D = 30 nm. D dependence of Delta agrees well with that expected from magnetic properties of blanket film taking into account the change in demagnetizing factors of MTJs. Intrinsic critical current (I-C0) reduces with decrease of D in the entire investigated D range. A ratio of D to IC0 shows continuous increase with decrease of D down to 11 nm. (C) 2014 AIP Publishing LLC.