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XAS and XMCD Investigation of Mn 12 Monolayers on Gold
Author(s) -
Mannini Matteo,
Sainctavit Philippe,
Sessoli Roberta,
Cartier dit Moulin Christophe,
Pineider Francesco,
Arrio MarieAnne,
Cornia Andrea,
Gatteschi Dante
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200800693
Subject(s) - magnetic circular dichroism , x ray absorption spectroscopy , x ray photoelectron spectroscopy , chemistry , manganese , analytical chemistry (journal) , magnetism , oxidation state , absorption spectroscopy , spectroscopy , ion , scanning tunneling microscope , crystallography , metal , materials science , spectral line , nuclear magnetic resonance , nanotechnology , condensed matter physics , physics , organic chemistry , quantum mechanics , astronomy , chromatography
Abstract The deposition of Mn 12 single molecule magnets on gold surfaces was studied for the first time using combined X‐ray absorption spectroscopy (XAS) and X‐ray magnetic circular dichroism (XMCD) methods at low temperature. The ability of the proposed approach to probe the electronic structure and magnetism of Mn 12 complexes without significant sample damage was successfully checked on bulk samples. Detailed information on the oxidation state and magnetic polarization of manganese ions in the adsorbates was obtained from XAS and XMCD spectra, respectively. Partial reduction of metal ions to Mn II was clearly observed upon deposition on Au(111) of two different Mn 12 derivatives bearing 16‐acetylthio‐hexadecanoate and 4‐(methylthio)benzoate ligands. The average oxidation state, as well as the relative proportions of Mn II , Mn III and Mn IV species, are strongly influenced by the deposition protocol. Furthermore, the local magnetic polarizations are significantly decreased as compared with bulk Mn 12 samples. The results highlight an utmost redox instability of Mn 12 complexes at gold surfaces, presumably accompanied by structural rearrangements, which cannot be easily revealed by standard surface analysis based on X‐ray photoelectron spectroscopy and scanning tunnelling microscopy.