Investigations on magnetostatic interactions among CoFeB layers with perpendicular anisotropy in [Ta/CoFeB/MgO]N multilayers

Abstract

The magnetostatic interactions among CoFeB layers with perpendicular anisotropy are studied in [Ta/CoFeB/MgO]N multilayers by measured loops, magnetic domains, and a simple model. With increasing repeat number N or decreasing separation thickness d between adjacent CoFeB layers, higher magnetostatic interaction among CoFeB layers results in bow-tie shape perpendicular loops and shrinking of domain size at remanence state. The measured nucleation field Hn of bow-tie shape perpendicular loops can be explained by a simple theoretical model including the intralayer and interlayer magnetostatic interactions among CoFeB layers with a certain domain size. © 2014 AIP Publishing LLC.