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Induced magnetic Cu moments and magnetic ordering in Cu2MnAl thin films on MgO(001) observed by XMCD

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The disorder–order transition of a highly defective A2-ordered Cu2MnAl film on MgO(0 0 1) upon annealing at 600 K was monitored by means of x-ray absorption spectroscopy (XAS) at the Cu and Mn L2,3 edges. Additionally, x-ray magnetic circular dichroism (XMCD) was employed to determine element-specific orbital and spin resolved magnetic moments of the Cu and Mn atoms. A small induced total magnetic moment of ≈0.04 ± 0.01μB per atom was detected at the Cu sites, whereas a total magnetic moment of 3.57 ± 0.52μB is carried by the Mn atoms. The experimental XAS and XMCD spectra of Cu agree reasonably with the results from ab initio calculations, magnetic moments derived by the sum rules are in accordance with the calculations.
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... The experimental lattice constants are used for the present calculations; a ¼ 5:96, 6.06, and 6.38 Å for Cu 2 -MnAl, Ni 2 MnSn, and Pd 2 MnSn, respectively. [35][36][37] The LDA and QSGW calculations for band structures are performed with 20 Â 20 Â 20 and 6 Â 6 Â 6 q-point mesh, respectively. In the calculations of K "# and R "# , we use 24 Â 24 Â 24 q-point mesh. ...
... The X-ray magnetic circular dichroism (XMCD) is accessible for the unoccupied states. 35) The Mn 3d components in the minority states can be detected by measuring the L 3 peak in the XMCD spectrum. In the Ref. 35, the L 3 peak was observed at slightly higher energy by ∼0.4 eV than the theoretical simulation within the LDA. ...
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... and 3.36/0.20 µ B for Cu and Mn, respectively 50 . Analyzing the projected density of states further for the various Ga doping in the Al site [c.f. ...
... This discrepancy could be due to the lack of electron core-hole Coulomb and exchange correlations. As reported earlier the 3d-Mn with nearly empty states gives strong L 2,3 absorption peaks due to strong photonelectron and core-hole interactions 50 . In the X-ray absorption spectroscopy spectra of Cu, we observed three prominent peaks denoted by 1, 2, and 3 at 1.0, 4.5, and 21.0 eV, respec- tively. ...
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