Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 26: Surface Magnetism
O 26.4: Vortrag
Dienstag, 6. September 2022, 11:15–11:30, H4
Magnetocrystalline anisotropy in two-dimensional EuAu2 and GdAu2: the role of band structure — •Maria Blanco-Rey1,2, Rodrigo Castrillo-Bodero3, Khadiza Ali2,3, Polina Sheverdyaeva4, Enrique Ortega1,3,2, Laura Fernandez3, and Frederik Schiller3,2 — 1Universidad del País Vasco UPV/EHU, Spain — 2Donostia International Physics Center, Spain — 3Centro de Física de Materiales CSIC-UPV/EHU-MPC, Donostia-San Sebastián, Spain — 4Instituto di Struttura della Materia ISM-CNR, Trieste, Italy
In rare earth (RE) intermetallic crystals, the magnetocrystalline anisotropy has a single-ion contribution from the f shell, often associated with a large orbital quantum number L, and an itinerant one, due to spin-orbit coupling effects in the band structure. As Eu and Gd are 4f7 RE atoms, L in 2D atom-thick EuAu2 and GdAu2 is essentially quenched. Therefore, these systems allow us to isolate the itinerant electron contribution in this 2D compound family. X-ray magnetic circular dichroism shows out-of-plane anisotropy in EuAu2, in contrast to in-plane in GdAu2. By means of angle-resolved photoemission and density-functional theory, we explain these behaviours in terms of the occupation of the spin-orbit-split dispersive RE(d)-Au(s) hybrid bands, which is ultimately dictated by the RE valence state (Eu2+ and Gd3+). In terms of energy, the itinerant electron contribution is ≈ 1 meV per unit cell, which may eventually compete with the single-ion contribution.