Electrical control of Co/Ni magnetism adjacent to gate oxides with low oxygen ion mobility

We investigate the electrical manipulation of Co/Ni magnetization through a combination of ionic liquid and oxide gating, where HfO₂ with a low O²⁻ ion mobility is employed. A limited oxidation-reduction process at the metal/HfO₂ interface can be induced by large electric field, which can greatly affect the saturated magnetization and Curie temperature of Co/Ni bilayer. Besides the oxidation/reduction process, first-principles calculations show that the variation of d electrons is also responsible for the magnetization variation. Our work discloses the role of gate oxides with a relatively low O²⁻ ion mobility in electrical control of magnetism, and might pave the way for the magneto-ionic memory with low power consumption and high endurance performance