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Probing Magnetic Excitations in Co^II^ Single-Molecule Magnets by Inelastic Neutron Scattering



Shelby E. Stavretis, Yongqiang Cheng, Luke L. Daemen, Craig Brown, Duncan H. Moseley, Eckhard Bill, Mihail Atanasov, A. J. Ramirez-Cuesta, Frank Neese, Zi-Ling Xue


Co(acac)2(H2O)2 (1 acac = acetylacetonate), a transition metal complex (S = 3/2), displays field-induced slow magnetic relaxation as a single-molecule magnet (SMMs). For 1 and its isotopologues Co(acac)2(D2O)2 (1-d4^) and Co(acac-d7)2(D2O)2 (1-D18) in appropriately D4th symmetry, Zero-field splitting of the ground electronic state leads to two Kramers doublets (KDs): lower energy Ms= ±1/2 (φ1,2) and higher energy Ms±3/2 (φ2,3) states. Inelastic neutron scattering (INS), a unique method to probe magnetic transitions, has been used to probe different magnetic excitations in 1. The direct-geometry, time-of-flight Disk-Chopper Spectrometer (DCS), with applied magnetic fields up to 10 T, has been used to study the intra-KD transition as a result of Zeeman splitting, Ms = -1/2 (φ1) arrow right} Ms = +1/2 (φ2), in 1=d18. This is a rare study of the Ms = -1/2 right arrow} Ms = +1/2 excitation in transition metal complexes by INS> The indirect-geometry INS spectrometer VISION has been sued to probe the inter-KD, SFS transition, Ms = + or -}1/2 (φ1,2) right arrow}Ms ±3/2 (φ3,4) in both 1-d4 and 1-d18. Variable-temperature (VT) properties of this excitation near 114 cm-1 have been used to identify the ZFS transition. The INS spectra measured on VISION also give phonon features of the complexes that are well described by ab initio phonon calculations.
European Journal of Inorganic Chemistry


Magnetism, single-molecule magnet, SMM, neutron scattering


Stavretis, S. , Cheng, Y. , Daemen, L. , Brown, C. , Moseley, D. , Bill, E. , Atanasov, M. , Ramirez-Cuesta, A. , Neese, F. and Xue, Z. (2019), Probing Magnetic Excitations in Co^II^ Single-Molecule Magnets by Inelastic Neutron Scattering, European Journal of Inorganic Chemistry, [online], (Accessed December 1, 2023)
Created February 27, 2019, Updated October 12, 2021