<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>3</mml:mn><mml:mi>d</mml:mi></mml:mrow></mml:math> oxide molecules to tailor large magnetic anisotropy energies on MgO films

Designing systems with large magnetic anisotropy energy (MAE) is desirable and critical for nanoscale magnetic devices. A recent breakthrough achieved the theoretical limit of the MAE for <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mn>3</a:mn><a:mi>d</a:mi></a:mrow></a:math> transition metal atoms by placing a single Co atom on a MgO(100) surface, a result not replicated by standard first-principles simulations. Our paper, incorporating Hubbard-<b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mi>U</b:mi></b:math> correction and spin-orbit coupling, successfully reproduces and explains the high MAE of a Co adatom on a MgO (001) surface. We go further by exploring ways to enhance MAE in <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mn>3</c:mn><c:mi>d</c:mi></c:mrow></c:math> transition metal adatoms through different structural geometries of <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mrow><d:mn>3</d:mn><d:mi>d</d:mi><d:mo>−</d:mo><d:mi mathvariant="normal">O</d:mi></d:mrow></d:math> molecules on MgO. One promising structure, with molecules perpendicular to the surface, enhances MAE while reducing substrate interaction, minimizing spin fluctuations, and boosting magnetic stability. Additionally, we demonstrate significant control over MAE by precisely placing <f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mrow><f:mn>3</f:mn><f:mi>d</f:mi><f:mo>−</f:mo><f:mi mathvariant="normal">O</f:mi></f:mrow></f:math> molecules on the substrate at the atomic level. Published by the American Physical Society 2024