First-Principles Prediction of Skyrmionic Phase Behavior in GdFe₂ Films Capped by 4<i>d</i> and 5<i>d</i> Transition Metals

Abstract

In atomic GdFe 2 films capped by 4d and 5d transition metals, we show that skyrmions with diameters smaller than 12 nm can emerge. The Dzyaloshinskii⁻Moriya interaction (DMI), exchange energy, and the magnetocrystalline anisotropy (MCA) energy were investigated based on density functional theory. Since DMI and MCA are caused by spin⁻orbit coupling (SOC), they are increased with 5d capping layers which exhibit strong SOC strength. We discover a skyrmion phase by using atomistic spin dynamic simulations at small magnetic fields of ∼1 T. In addition, a ground state that a spin spiral phase is remained even at zero magnetic field for both films with 4d and 5d capping layers.

Keywords

• skyrmion
• Dzyaloshinskii–Moriya interaction
• exchange energy
• magnetic anisotropy