Effect of interface on magnetic properties of Co20Fe60B20 in ion-beam sputtered Si/CoFeB/MgO and Si/MgO/CoFeB bilayers

► Dependence of the magnetic response of CoFeB on interface with MgO. ► Growth methods studied for MgO are post-oxidation, reactive and ion-assisted growth. ► Significant amount of in-plane magnetic anisotropy observed for CoFeB(top)/MgO. ► Absence of in-plane magnetic anisotropy in MgO/CoFeB(bottom).