Interface Design for Concurrent Realization of High Perpendicular Magnetic Anisotropy and Low Magnetic Damping in Fe/MgO

In spin transfer torque magnetoresistive random-access memory (STT-MRAM) the problem in writing mechanism arises mainly due to the need of large current to switch magnetization direction of the free ferromagnet layer. As the device development of 1X nm cell diameter is preferable, keeping thermal stability to suppress data retention failures while maintaining fast switching mechanism become challenging since there is a trade-off relationship of magnetic anisotropy and magnetic damping between material and devices. The Fe/MgO system reported as a superior structure for magnetic tunnel junctions owing to the high tunnel magnetoresistance and perpendicular magnetic anisotropy (PMA). Modifying Fe/MgO interface using thin layer materials offer prospect of achieving high PMA and low magnetic damping simultaneously. The work focuses in exploring interface engineering by implementing thin layer materials, specifically by inserting the nitride and fluoride thin layers, to achieve magnetic tunnel junction (MTJ) design with high PMA and low magnetic damping from first principles. The result signifies that the Fe/LiF/MgO, Fe/BN/MgO, and Fe/MgN/MgO modification models achieve a high PMA enhancement up to 350% while simultaneously reducing magnetic damping about 80% lower than those in the pristine Fe/MgO model. The origins are majorly driven by the Fe - <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> orbitals realignment at around Fermi level.