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Influence of lanthanides on spin-relaxation and spin-structure in a family of Fe(7)Ln(4) single molecule magnets

TitleInfluence of lanthanides on spin-relaxation and spin-structure in a family of Fe(7)Ln(4) single molecule magnets
Publication TypeJournal Article
Year of Publication2018
AuthorsProdius, D, Mereacre, V, Singh, P, Lan, YH, Mameri, S, Johnson, DD, Wernsdorfer, W, Anson, CE, Powell, AK
JournalJournal of Materials Chemistry C
Volume6
Pagination2862-2872
Date Published03
Type of ArticleArticle
ISBN Number2050-7526
Accession NumberWOS:000428999300028
Keywordsaugmented-wave, coordination clusters, dy-iii, fe-57 mossbauer-spectroscopy, fe-iii, ground-state, Ionic, ligand substitution, liquids, Materials Science, method, physics, susceptibility measurements, total-energy calculations
Abstract

A family of isostructural undecanuclear 3d-4f coordination clusters of formula [Fe(7)(III)Ln(4)(III)O(4)(OH)(3)(tea)(20)-(Htea)(3)(Piv)(7)(H2O)(2)(NO3)(3)], where Ln = Y (1), Gd (2), Tb (3), Dy (4); PivH equivalent to pivalic acid and H(3)tea equivalent to triethanolamine, was synthesised. The central Fe-7 core of the coordination cluster can be described in terms of two {Fe4O2} butterfly motifs sharing a common body Fe atom. The two Fe-4 mean-planes subtend a dihedral angle of ca. 72 degrees. The Tb (3) and Dy (4) compounds show Single Molecule Magnet (SMM) behaviour as confirmed by ac-susceptibility and mu-SQUID measurements. Furthermore, Fe-57 Mossbauer spectra of 1-4 confirm the presence of high-spin Fe-III sites. The spectra of all complexes in the high temperature range (30-300 K) show broad overlapping doublets which were assigned to the body and wing-tip pairs of metal ions within the Fe7 core. The low temperature Mossbauer spectra show dependence on the nature of the rare-earth metal as a result of its interaction with the iron sites. Thus, we observed a transition from fast (2), to intermediate (1) and very slow (frozen) (3, 4) spin fluctuation phenomena in these compounds.

DOI10.1039/c8tc00322j
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