Manipulation of magnetism in perpendicularly magnetized Heusler alloy Co2FeAl0.5Si0.5 by electric-field at room temperature

The electrical manipulation of magnetic properties in perpendicularly magnetized Co2FeAl0.5Si0.5 ultra-thin films has been investigated. An electric-field is applied by utilizing either a solid-state dielectric HfO2 film or an ionic gel film as the gate insulator in the form of a field effect parallel capacitor. Obvious changes of the coercive field and Curie temperature (∼24 K) by gating voltage are observed for a 0.8 nm thick film, while a clear change of the magnetic anisotropy is obtained for the 1.1 nm thick one. The experimental results have been attributed to both the electric-field-induced modulation of carrier density near the interface and the oxidation-reduction effect inside the magnetic films.