title: Field-induced slow relaxation of magnetization in a pentacoordinate Co(II) compound [Co(phen)(DMSO)Cl2].
abstract: The static and dynamic magnetic properties of a pentacoordinate [Co(phen)(DMSO)Cl2] compound (phen = 1,10'-phenanthroline, DMSO = dimethyl sulfoxide) were thoroughly studied by experimental (SQUID magnetometry and HF-EPR spectroscopy) and theoretical methods (DFT and CASSCF calculations). It has been found from temperature/field-dependent magnetization measurements that the studied compound possesses a large and negative magnetic anisotropy (D = -17(1) cm(-1)) with large rhombicity (E/D = 0.24(5)), and these experimental results are in agreement with ab initio calculations (D = -17.7 cm(-1), E/D = 0.31). Interdoublet resonances were not observed in the HF-EPR measurements, but the large rhombicity was confirmed (DEPR = -17.7 cm(-1) (fixed from CASSCF calculations), E/DEPR = 0.33). A frequency dependent out-of-phase susceptibility signal was observed only in a non-zero static magnetic field (B = 0.1 T) and the following parameters of slow-relaxation of magnetisation were derived from the experimental data: either the energy of spin reversal barrier, Ueff = 10.4 K, and the relaxation time, τ0 = 5.69 × 10(-9) s using the Debye model, or Ueff = 21.4-40.3 K and τ0 = 0.248-58.3 × 10(-9) based on a simplified model.
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Inorganic Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, CZ-771 46 Olomouc, Czech Republic. zdenek.travnicek@upol.cz.
authors.forename: Ivan
authors.initials: I
authors.lastname: Nemec
authors.forename: Raphael
authors.initials: R
authors.lastname: Marx
authors.forename: Radovan
authors.initials: R
authors.lastname: Herchel
authors.forename: Petr
authors.initials: P
authors.lastname: Neugebauer
authors.forename: Joris
authors.initials: J
authors.lastname: van Slageren
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Trávníček