Magnetic-field-angle dependence of coercivity in CoFeB/MgO magnetic tunnel junctions with perpendicular easy axis.

We investigate the magnetization-reversal mode in CoFeB/MgO magnetic tunnel junctions with perpendicular easy axis from the magnetic-field-angle dependence of coercivity. The reversal in a free layer with diameter of ~20 nm is found to be in a good agreement with coherent reversal mode for a device with a reference layer much larger than the free layer. However, the reversal mode is quite different in a junction in which the two layers are almost the same size. From micro-magnetic simulation, the difference is attributed to the reduction of the magnetic anisotropy in the vicinity of the device edge. [ABSTRACT FROM AUTHOR]