Adding Remnant Magnetization and Anisotropic Exchange to Propeller‐like Single‐Molecule Magnets through Chemical Design. Issue 42 (8th September 2014)

• Record Type: Journal Article
• Authors: Westrup, Kátia Cristina M.; Boulon, Marie‐Emmanuelle; Totaro, Pasquale; Nunes, Giovana G.; Back, Davi F.; Barison, Andersson; Jackson, Martin; Paulsen, Carley; Gatteschi, Dante; Sorace, Lorenzo; Cornia, Andrea; Soares, Jaísa F.; Sessoli, Roberta
• Is Part Of: Chemistry. Volume 20:Issue 42(2014)
• Page Start: 13681
• Page End: 13691
• Publication Date: 2014-09-08
• Subjects: iron -- magnetic anisotropy -- molecular magnetism -- single‐molecule magnets -- vanadium; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201403361
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The selective replacement of the central iron(III) ion with vanadium(III) in a tetrairon(III) propeller‐shaped single‐molecule magnet has allowed us to increase the ground spin state from S =5 to S =13/2. As a consequence of the pronounced anisotropy of vanadium(III), the blocking temperature for the magnetization has doubled. Moreover, a significant remnant magnetization, practically absent in the parent homometallic molecule, has been achieved owing to the suppression of zero‐field tunneling of the magnetization for the half‐integer molecular spin. Interestingly, the contribution of vanadium(III) to the magnetic anisotropy barrier occurs through the anisotropic exchange interaction with iron(III) spins and not through single ion anisotropy as in most single‐molecule magnets. Abstract : Molecular magnetism : A significant increase in the hysteretic behavior of the magnetization in propeller‐like Fe4 single‐molecule magnets (SMMs) has been achieved by replacing the central Fe III ion with V III (see figure), with suppression of zero‐field tunneling in this half‐integer spin system. An increase in the anisotropy barrier is also observed, although V III is expected to exhibit hard axis anisotropy in trigonal symmetry. Anisotropy of the Fe–V exchange interaction overwhelms the unfavorable anisotropy of V III .