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Perpendicular magnetic anisotropy of two-dimensional Rashba ferromagnets

Published

Author(s)

Kyoung-Whan Kim, Kyung Jin Lee, Hyun-Woo Lee, Mark D. Stiles

Abstract

We compute the magnetocrystalline anisotropy energy within two-dimensional Rashba models. For a free- electron Rashba model with infinite band width and infinite Brillouin zone, the anisotropy is exactly zero no matter how strong the Rashba coupling is, unless only the lowest band is occupied. For this special case, the model predicts in-plane anisotropy. We then consider a more realistic Rashba model with finite band width and finite Brillouin zone. We find that a Rashba model with finite band width predicts the evolution from in-plane to perpendicular and back to in-plane magnetic anisotropy as bands are progressively filled. This evolution agrees with first-principles calculations on the interfacial anisotropy. This suggests that the Rashba model captures energetics leading to the anisotropy of interfacial origin, once the model is augmented to take account of the finite band width and finite Brillouin zone. We show that the electron density modulation by doping or an external voltage is more important for voltage-controlled magnetic anisotropy than the modulation of the Rashba parameter.
Citation
Physical Review B
Volume
94

Keywords

magnetic anisotropy, spin-orbit coupling, Rashba effect

Citation

Kim, K. , , K. , Lee, H. and Stiles, M. (2016), Perpendicular magnetic anisotropy of two-dimensional Rashba ferromagnets, Physical Review B, [online], https://doi.org/10.1103/PhysRevB.94.184402 (Accessed April 17, 2024)
Created November 3, 2016, Updated November 10, 2018