Microscopic spin Hamiltonian of a Cr 8 antiferromagnetic ring from inelastic neutron scattering

Exchange integrals and single-ion anisotropy parameters of a ring-shaped molecular cluster, comprising eight chromium(III) ions $(s=3/2)$ were determined by inelastic neutron scattering. Effects due to the mixing of different spin multiplets have been considered. Such effects proved to be important to correctly reproduce the relative intensity of magnetic excitations in the neutron spectra. Evidence of decreasing lifetimes with increasing energy of excited spin states was found. The microscopic picture emerging from neutron spectroscopy was confirmed by the temperature dependence of the heat capacity.

[1]  Jansen,et al.  Tuning of Magnetic Anisotropy in Hexairon(III) Rings by Host-Guest Interactions: An Investigation by High-Field Torque Magnetometry. , 1999, Angewandte Chemie.

[2]  Stefano Carretta,et al.  S-mixing contributions to the high-order anisotropy terms in the effective spin Hamiltonian for magnetic clusters , 2002 .

[3]  C. Meyers,et al.  Effect of Ligand Deuteration on the Decay of Eu3+(5D0) in Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)europium(III) , 1998 .

[4]  H. Güdel,et al.  Neutron inelastic scattering from isolated clusters of magnetic ions , 1979 .

[5]  M. Affronte,et al.  Magnetic anisotropy of Fe 6 and Fe 10 molecular rings by cantilever torque magnetometry in high magnetic fields , 1999 .

[6]  A. Lascialfari,et al.  Spin dynamics in mesoscopic size magnetic systems: A {sup 1}HNMR study in rings of iron (III) ions , 1997 .

[7]  A. Caneschi,et al.  Large Clusters of Metal Ions: The Transition from Molecular to Bulk Magnets , 1994, Science.

[8]  S. Carretta,et al.  Neutron spectroscopy within the S=5 groud multiplet and low-temperature heat capacity in Fe4 magnetic cluster , 2001 .

[9]  A. Barra,et al.  Magnetic anisotropy of the antiferromagnetic ring [Cr8F8Piv16]. , 2002, Chemistry.

[10]  A. Barra,et al.  Disorder effects in Mn(12)-acetate at 83 K. , 2002, Acta crystallographica. Section C, Crystal structure communications.

[11]  A. Caneschi,et al.  Inelastic neutron scattering below 85 μeV and zero-field splitting parameters in the Fe 8 magnetic cluster , 2000 .

[12]  L. Brunel,et al.  Single-ion versus dipolar origin of the magnetic anisotropy in iron(III)-oxo clusters: a case study. , 2001, Chemistry.

[13]  A. Caneschi,et al.  Neutron transitions within the S=10 ground multiplet of a Fe 8 magnetic cluster , 2002 .

[14]  D. Gatteschi,et al.  MAGNETIC PROPERTIES OF HIGH NUCLEARITY SPIN CLUSTERS. A FAST AND EFFICIENTPROCEDURE FOR THE CALCULATION OF THE ENERGY LEVELS , 1993 .

[15]  A. Caneschi,et al.  Magnetic bistability in a metal-ion cluster , 1993, Nature.

[16]  R. Koch,et al.  Magnetic Anisotropy of Two Cyclic Hexanuclear Fe(III) Clusters Entrapping Alkaline Ions , 1999 .

[17]  J. J. Borrás-Almenar,et al.  High-Nuclearity Magnetic Clusters: Generalized Spin Hamiltonian and Its Use for the Calculation of the Energy Levels, Bulk Magnetic Properties, and Inelastic Neutron Scattering Spectra. , 1999, Inorganic chemistry.

[18]  D. Physics,et al.  Single-Crystal High-Frequency Electron Paramagnetic Resonance Investigation of a Tetranuclear Iron(III) Single-Molecule Magnet , 2001, cond-mat/0101255.

[19]  O. Waldmann.  Symmetry and energy spectrum of high-nuclearity spin clusters , 2000 .

[20]  Michael N. Leuenberger,et al.  Quantum computing in molecular magnets , 2000, Nature.

[21]  M. Affronte,et al.  Low temperature specific heat of molecular rings: a study on the effects of the internal guest substitution and on the lattice contribution , 2000 .

[22]  A. Caneschi,et al.  Neutron Spectroscopy for the Magnetic Anisotropy of Molecular Clusters , 1998 .

[23]  A. Caneschi,et al.  Magnetic and structural properties of an octanuclear Cu(II) S=1/2 mesoscopic ring: Susceptibility and NMR measurements , 2000 .

[24]  A. Caneschi,et al.  The molecular approach to nanoscale magnetism , 1999 .

[25]  R. Koch,et al.  Magnetic anisotropy of a cyclic octanuclear Fe(III) cluster and magneto-structural correlations in molecular ferric wheels. , 2001, Inorganic chemistry.

[26]  Friedman,et al.  Macroscopic measurement of resonant magnetization tunneling in high-spin molecules. , 1996, Physical review letters.

[27]  Andrea Caneschi,et al.  A Cyclic Octadecairon(III) Complex, the Molecular 18‐Wheeler , 1997 .

[28]  L. Thomas,et al.  Macroscopic quantum tunnelling of magnetization in a single crystal of nanomagnets , 1996, Nature.

[29]  A. Caneschi,et al.  Structure and Magnetic Properties of a Dodecanuclear Twisted-Ring Iron(III) Cluster. , 1999, Angewandte Chemie.

[30]  M. Pilkington,et al.  High-Spin Molecules: A Novel Cyano-Bridged MnMo Molecular Cluster with aS=51/2 Ground State and Ferromagnetic Intercluster Ordering at Low Temperatures , 2000 .

[31]  W. Wernsdorfer,et al.  Quantum phase interference and parity effects in magnetic molecular clusters , 1999, Science.