Cyrus F. Hirjibehedin, Chiung-Yuan Lin, Alexander F. Otte, Markus Ternes, Christopher P. Lutz, Barbara A. Jones, and Andreas J. Heinrich, "Large Magnetic Anisotropy of a Single Atomic Spin Embedded in a Surface Molecular Network," Science 317, 1199 (2007).

Anisotropy for Mn

Mn vs Fe anisotropy

Fe spin vs Field

Eigenstates for axial anisotropy