Orbital moment anisotropy in ultrathin FePt layers

Marcio Soares (1) , Anne Lamirand (1) , Aline Y. Ramos (2) , Maurizio de Santis (1) , Hélio C. N. Tolentino (3)

1 NEEL - SIN - Surfaces, Interfaces et Nanostructures
2 NEEL - MRS - Matériaux, Rayonnements, Structure
3 NEEL - CRG - CRG & Grands instruments

The anisotropy of the Fe orbital moment is investigated in epitaxial ultrathin (<2 nm) FePt layers by angular dependent x-ray magnetic circular dichroism (XMCD) for two distinct epitaxial systems, CoO/FePt/Pt(001) and Pt/FePt/MnPt/Pt(001). Element selective hysteresis loops obtained from the XMCD signal at the Fe L 3 edge are used to quantify the anisotropy constants, which are consistent with the corresponding chemical order parameter. A careful procedure for XMCD sum rules data analysis is set up to avoid experimental overestimation of the orbital moment. The measured orbital moment of Fe is found comparable to theoretical values and shows a significant anisotropy. This orbital moment anisotropy is discussed in the light of the current theoretical understanding of magnetocrystalline anisotropy in ordered alloys.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Marcio Soares, Anne Lamirand, Aline Y. Ramos, Maurizio de Santis, Hélio C. N. Tolentino. Orbital moment anisotropy in ultrathin FePt layers. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2014, 90 (21), pp.214403. ⟨10.1103/PhysRevB.90.214403⟩. ⟨hal-01224306⟩