title: Magnetic relaxation pathways in lanthanide single-molecule magnets.
abstract: Single-molecule magnets are compounds that exhibit magnetic bistability caused by an energy barrier for the reversal of magnetization (relaxation). Lanthanide compounds are proving promising as single-molecule magnets: recent studies show that terbium phthalocyanine complexes possess large energy barriers, and dysprosium and terbium complexes bridged by an N2(3-) radical ligand exhibit magnetic hysteresis up to 13 K. Magnetic relaxation is typically controlled by single-ion factors rather than magnetic exchange (whether one or more 4f ions are present) and proceeds through thermal relaxation of the lowest excited states. Here we report polylanthanide alkoxide cage complexes, and their doped diamagnetic yttrium analogues, in which competing relaxation pathways are observed and relaxation through the first excited state can be quenched. This leads to energy barriers for relaxation of magnetization that exceed 800 K. We investigated the factors at the lanthanide sites that govern this behaviour.
authors.affiliation: School of Chemistry and Photon Science Institute, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Blagg
authors.forename: Liviu
authors.initials: L
authors.lastname: Ungur
authors.forename: Floriana
authors.initials: F
authors.lastname: Tuna
authors.forename: James
authors.initials: J
authors.lastname: Speak
authors.forename: Priyanka
authors.initials: P
authors.lastname: Comar
authors.forename: David
authors.initials: D
authors.lastname: Collison
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wernsdorfer
authors.forename: Eric J L
authors.initials: EJ
authors.lastname: McInnes
authors.forename: Liviu F
authors.initials: LF
authors.lastname: Chibotaru
authors.forename: Richard E P
authors.initials: RE
authors.lastname: Winpenny
mesh_terms: D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008280:Magnetics; D015394:Molecular Structure
chemical_list: D028581:Lanthanoid Series Elements