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Static and dynamic magnetic properties of split CoFeB/Ta/CoFeB/MgO stacks grown on W underlayers



A. Kaidatzis, Daniel Gopman, C. Bran, J. M. Garcia-Martin, M. Vazquez, D. Niarchos


We report on the static and dynamic properties of W/CoFeB/Ta/CoFeB/MgO stacks, where the CoFeB layer is split in two by a 0.3 nm-thick Ta "dusting" layer. A total CoFeB thickness between 1.2 and 2.4 nm is studied. Perpendicular magnetic anisotropy is obtained even in the as-deposited stacks, whereas the perpendicular to in-plane anisotropy transition, after annealing, occurs at approximately 1.8 nm thickness. Saturation magnetization is 1520 (1440) kA/m before (after) annealing, increased compared to non-split CoFeB layers. Ferromagnetic resonance measurements show that high magnetic anisotropy energy may be achieved (effective anisotropy field 0.571±0.003 T), combined with a moderate Gilbert damping (0.030±0.001). We argue that the above characteristics make the split-CoFeB system advantageous for spintronics applications.
Applied Physics Letters


spintronics, nanomagnetism, magnetic anisotropy


Kaidatzis, A. , Gopman, D. , Bran, C. , Garcia-Martin, J. , Vazquez, M. and Niarchos, D. (2018), Static and dynamic magnetic properties of split CoFeB/Ta/CoFeB/MgO stacks grown on W underlayers, Applied Physics Letters, [online],, (Accessed April 20, 2024)
Created October 21, 2018, Updated October 12, 2021