Influence of Ta insertions on the magnetic properties of MgO/CoFeB/MgO films probed by ferromagnetic resonance

摘要

We show by vector network analyzer ferromagnetic resonance measurements thatlow Gilbert damping {\alpha} down to 0.006 can be achieved in perpendicularlymagnetized MgO/CoFeB/MgO thin films with ultra-thin insertions of Ta in theCoFeB layer. While increasing the number of Ta insertions allows thicker CoFeBlayers to remain perpendicular, the effective areal magnetic anisotropy doesnot improve with more insertions, and also comes with an increase in {\alpha}.