RKKY-like contributions to the magnetic anisotropy energy: 3d adatoms on Pt(111) surface

TL;DR

This paper demonstrates that long-range RKKY-like interactions significantly influence the magnetic anisotropy energy of 3d adatoms on Pt(111), revealing oscillatory behavior and site-dependent effects through density functional theory simulations.

Contribution

It introduces the role of RKKY-like contributions in modifying magnetic anisotropy energy, supported by analytical and computational analysis for transition metal adatoms.

Findings

Magnetic anisotropy energy is strongly affected by long-range oscillations.

Site-dependent variations in anisotropy energy are explained by RKKY-like interactions.

Oscillatory behavior of anisotropy energy can switch its sign in realistic materials.

Abstract

The magnetic anisotropy energy defines the energy barrier that stabilizes a magnetic moment. Utilizing density functional theory based simulations and analytical formulations, we establish that this barrier is strongly modified by long-range contributions very similar to Frieden oscillations and Rudermann-Kittel-Kasuya-Yosida interactions. Thus, oscillations are expected and observed, with different decaying factors and highly anisotropic in realistic materials, which can switch non-trivially the sign of the magnetic anisotropy energy. This behavior is general and for illustration we address transition metals adatoms, Cr, Mn, Fe and Co deposited on Pt(111) surface. We explain in particular the mechanisms leading to the strong site-dependence of the magnetic anisotropy energy observed for Fe adatoms on Pt(111) surface as revealed previously via first-principles based simulations and inelastic scanning tunneling spectroscopy (A. A. Khajetoorians et al. Phys. Rev. Lett. 111, 157204 (2013)). The same mechanisms are probably active for the site-dependence of the magnetic anisotropy energy obtained for Fe adatoms on Pd or Rh(111) surfaces and for Co adatoms on Rh(111) surface (P. Blonski et al. Phys. Rev. B 81, 104426 (2010)).