Orbital magnetism and magnetic anisotropy probed with ferromagnetic resonance

Via ferromagnetic resonance both the magnetic anisotropy energy (MAE) and the spectroscopic splitting tensor (g tensor) for a bcc Fe-2/V-5(001) superlattice are measured independently. The theoretically proposed proportionality between the anisotropy of the orbital moment mu(L) and the MAE is quantitatively checked and its limitations are discussed. From layer-resolved first-principles calculations we find a reduced spin moment mu(S) = 1.62 mu(B) for Fe and mu(S)(V) = -0.67 mu(B) in the first V layer. The g-tensor elements reveal a 300% enhanced ratio mu(L)/mu(S) = 0.133 in comparison to bulk Fe. The MAE and the orbital moment anisotropy is found to be unusually small for Fe monolayers.