Mechanism of magnetization enhancement at the Fe/LiF/MgO interface elucidated through the first-principles calculations of the interface structure

Abstract

Nonvolatile magnetic memory is attracting considerable attention as a next-generation type of magnetic memory that does not require electric power to retain information. The interface between iron and magnesium oxide is one of the candidate solutions for realizing this type of memory. Recent experiments have shown that the insertion of a LiF monolayer at the interface between Fe and MgO results in a twofold enhancement in perpendicular magnetic anisotropy. Herein, we used density functional theory to calculate the magnetic moments at the interface between Fe and MgO and between Fe/LiF and MgO. Our results indicate that the insertion of LiF at the interface leads to a doubling of the magnetic moment because of the tilting of electron orbitals in Fe atoms near the interface toward the minimum electron density site located at the diagonal intersection of the LiF lattice. Our findings provide a new guideline for exploring candidate materials for high-performance nonvolatile magnetic memory.