Electric-field effect on magnetic anisotropy in Pt/Co/Pd/MgO structures deposited on GaAs and Si substrates

We investigate the electric-field effect on the magnetic anisotropy in perpendicularly magnetized Pt/Co/Pd/MgO structures deposited on GaAs and Si substrates as a function of temperature. An electric field is applied to the Pd surface through a 2-nm-thick insulating MgO layer by forming an electric double layer using an ionic liquid. We find that the electric-field dependence of the anisotropy is similar but clearly different between the two samples at low temperatures. The difference is expected to be related to the difference in the internal strain of the two structures.