Single crystal EPR determination of the spin Hamiltonian parameters for Fe8 molecular clusters
| Autor: | M. M. Mola, N. S. Dalal, Ezana Negusse, R. M. Achey, A. Lussier, S. Maccagnano, Stephen Hill |
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| Rok vydání: | 2001 |
| Předmět: |
Condensed matter physics
Chemistry Field dependence Molecular physics Spectral line Inelastic neutron scattering law.invention Magnetic field Inorganic Chemistry Magnetic anisotropy symbols.namesake law Materials Chemistry symbols Physical and Theoretical Chemistry Electron paramagnetic resonance Hamiltonian (quantum mechanics) Single crystal |
| Zdroj: | Polyhedron. 20:1441-1445 |
| ISSN: | 0277-5387 |
| Popis: | We use a multi-high-frequency resonant cavity technique to obtain EPR spectra for single crystal samples of the biaxial molecular magnet Fe 8 [(tacn) 6 O 2 (OH) 12 ]Br 8 ·9H 2 O (Fe 8 ). By performing measurements at many closely spaced frequencies, we are able to extrapolate data back to zero magnetic field and, thereby, obtain accurate estimates of the zero-field splittings. Furthermore, from the (low-) field dependence of these splittings, with the magnetic field parallel to the easy axis, we can directly measure the g z -value. Measurements performed with the magnetic field parallel to the intermediate and hard axes may be used to constrain further the Hamiltonian parameters. Our results are in broad agreement with recent inelastic neutron scattering data. In addition, analysis of individual resonances (which we can assign to known transitions) reveals a pronounced M S dependence of the resonance line widths. Furthermore, the line positions exhibit complex (again M S dependent) temperature dependences that cannot be reconciled with the standard spin Hamiltonian. |
| Databáze: | OpenAIRE |
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