Tuning magnetic anisotropy and magnetization switching in FeN ferromagnetic films by crystal regulation

摘要

Tailoring the magnetic anisotropy and magnetization switching of a ferromagnetic film is crucial in constructing an energy-efficient magnetic random access memory (MRAM). Fe16N2 alloy was predicted to bear giant magnetic anisotropy and high spin polarization ratio in theory and is a promising material to be applied in the magnetic memory devices. However, the related research work was scarcely reported. In this work, we devised a Fe/Cr/ FeN/Cr heterostructure to introduce a controllable strain on the FeN layer by a lattice mismatch. The strain is variable with the thickness of FeN layer and can modify the phase constituent in the FeN layer effectively. By using the strain engineering, we achieved a broad tunability of magnetic anisotropy energy ranging 0.1-0.7 x 10(6) J/m(3). Based on the anisotropy modulation, we achieved electrical control of partial magnetization switching in the Fe/Cr/FeN/Pt heterostructure by a spin-orbit-toque (SOT) effect under a current density similar to 10(10) A/m(2). These findings may provide a promising ferromagnetic material for realizing energy-efficient SOT-MARM.