Giant perpendicular magnetic anisotropy in Fe/III-V nitride thin films

TL;DR

This study reveals unprecedented giant perpendicular magnetic anisotropy in Fe/III-V nitride thin films, driven by first-order spin-orbit coupling effects, surpassing previous materials and opening new avenues in nanomagnetism and spintronics.

Contribution

First-principles calculations demonstrate giant PMA in Fe/III-V nitride thin films, with a novel mechanism involving first-order spin-orbit coupling effects.

Findings

PMA ranges from 24.1 to 53.7 meV/u.c.

Symmetry-protected degeneracy is lifted by spin-orbit coupling.

First-order perturbation dominates PMA in these films.

Abstract

Large perpendicular magnetic anisotropy (PMA) in transition metal thin films provides a pathway for enabling the intriguing physics of nanomagnetism and developing broad spintronics applications. After decades of searches for promising materials, the energy scale of PMA of transition metal thin films, unfortunately, remains only about 1 meV. This limitation has become a major bottleneck in the development of ultradense storage and memory devices. We discovered unprecedented PMA in Fe thin-film growth on the $(000\bar{1})$ N-terminated surface of III-V nitrides from first-principles calculations. PMA ranges from 24.1 meV/u.c. in Fe/BN to 53.7 meV/u.c. in Fe/InN. Symmetry-protected degeneracy between $x^2-y^2$ and $xy$ orbitals and its lift by the spin-orbit coupling play a dominant role. As a consequence, PMA in Fe/III-V nitride thin films is dominated by first-order perturbation of the spin-orbit coupling, instead of second-order in conventional transition metal/oxide thin films. This game-changing scenario would also open a new field of magnetism on transition metal/nitride interfaces.