Precise chemical, electronic, and magnetic structure of binuclear complexes studied by means of X-ray spectroscopies and theoretical methods

Kuepper, Karsten; Benoit, David M.; Wiedwald, Ulf; Mögele, Florian; Meyering, Andreas; Neumann, Manfred; Kappler, Jean-Paul; Joly, Loïc; Weidle, Stefan; Rieger, Bernhard; Ziemann, Paul

Abstract

We investigate two planar complexes MnNi and CoNi (see Scheme 1) by X-ray photoelec- tron spectroscopy (XPS) and ultralow-temperature X-ray magnetic circular dichroism (XMCD). In this way the valence states as well as the presence of uncompensated magnetic moments are obtained. The magnetism has been probed at a temperature of 0.6 K in order to reveal the magnetic ground state properties. We find that divalent Ni ions are in a diamagnetic low spin ground state in both complexes; however, in MnNi a small fraction of divalent nickel high-spin ions leads to a residual XMCD signal, indicating parallel spin alignment with the Mn spins. Mn and Co are found to be in a divalent high-spin configuration in both compounds. Theoretically, we address the energetic ordering of the different possible spin states of the binuclear complexes using (zeroth-order) relativistic approximation density functional calculations and a triple-ζ quality basis set. These results show that intermediate-spin states are often favored over low-spin states for most both metal combinations, in qualitative agreement with our experimental observations.

Citation

Kuepper, K., Benoit, D. M., Wiedwald, U., Mögele, F., Meyering, A., Neumann, M., Kappler, J.-P., Joly, L., Weidle, S., Rieger, B., & Ziemann, P. (2011). Precise chemical, electronic, and magnetic structure of binuclear complexes studied by means of X-ray spectroscopies and theoretical methods. Journal of physical chemistry. C, 115(50), 25030-25039. https://doi.org/10.1021/jp2069804

• Journal Article Type: Article
• Acceptance Date: Oct 26, 2011
• Online Publication Date: Nov 28, 2011
• Publication Date: Dec 22, 2011
• Journal: Journal of Physical Chemistry C
• Print ISSN: 1932-7447
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 115
• Issue: 50
• Pages: 25030-25039
• DOI: https://doi.org/10.1021/jp2069804
• Keywords: General Energy; Physical and Theoretical Chemistry; Electronic, Optical and Magnetic Materials; Surfaces, Coatings and Films
• Public URL: https://hull-repository.worktribe.com/output/424098