Perpendicular Magnetic Anisotropy Electric Field Modulation in Magnetron-Sputtered Pt/Co/X/MgO Ultrathin Structures With Chemically Tailored Top Interface

Ab initio calculations of voltage-controlled perpendicular magnetic anisotropy predict that the adjunction of Pt at the top of Co/MgO interface in Pt/Co/MgO ultrathin structures would enhance the perpendicular anisotropy and its electric field ( E-field) variation rate. Following these theoretical expectations, using the magnetron-sputtering technique, we first designed and elaborated magnetic multilayered samples which have subsequently been patterned by UV lithography in magnetotransport devices. The as-deposited samples show perpendicular magnetization configuration whose E-field modulation has been studied by anomalous Hall effect magnetometry experiments under applied E-field in patterned devices. The measured voltage anisotropy modulation effect is found to be asymmetric with respect to the E-field polarity, in qualitative agreement with theoretical predictions.