We have investigated the effect of applied electric field EG on thickness dependent magnetic anisotropy of sputtered Co40Fe40B 20 sandwiched with MgO and Ta. The range of CoFeB thickness explored is 2 nm and below. As the thickness is reduced, the easy axis of magnetization becomes perpendicular from in-plane. We show that perpendicular magnetic anisotropy of in-plane samples and coercivity of perpendicular samples can be modified by applying EG at room temperature. Furthermore, superparamagnetic behavior is observed for CoFeB layers with further reduced thickness below ≈0.9 nm, where electric-field effect is also observed below their blocking temperature.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)