Session V43: Low Dimensional Magnetism: Clusters & Molecules
11:15 AM–1:51 PM, Thursday, March 24, 2005
LACC Room: 150C
Sponsoring Unit:
GMAG
Chair: V. Kiryukhin, Rutgers University
Abstract ID: BAPS.2005.MAR.V43.1
Abstract: V43.00001 : Neutron Magnetic Excitation Study of the Giant Magnetic Molecule {\{}Mo$_{72}$Fe$_{30}${\}}
11:15 AM–11:27 AM
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Authors:
V.O. Garlea
(Ames Lab.\& ISU, Ames, IA, USA)
S.E. Nagler
(ORNL, Oak Ridge, TN, USA)
J.L. Zarestky
C. Stassis
D. Vaknin
P. Kogerler
(Ames Lab.\& ISU, Ames, IA, USA)
D.F. McMorrow
(Univ. College London, UK)
C. Niedermayer
(Lab. Neutron Scattering PSI, Switzerland)
Y. Qiu
(NCNR, Gaithersburg, MA, USA )
D.A. Tennant
(Univ. St Andrews, Scotland, UK)
B. Lake
(Clarendon Lab, Univ. Oxford, UK)
M. Exler
J. Schnack
(Univ. Osnabruck, Germany)
M. Luban
(Ames Lab.\& ISU, Ames, IA, USA)
We report cold-neutron inelastic scattering measurements on deuterated samples of {\{}Mo$_{72}$Fe$_{30}${\}} Keplerate. The nanocluster {\{}Mo$_{72}$Fe$_{30}${\}} is a molecular quasi-sphere in which 30 Fe$^{3+}$ ions (S = 5/2) occupy the vertices of an icosidodecahedron. The spins interact via an isotropic AF exchange coupling between nearest-neighbors. The measurements reveal a magnetic excitation spectrum that can be interpreted within the context of an effective three-sublattice Hamiltonian model. At mK temperatures, an excitation at E $\sim $ 0.63 meV is observed that can be attributed to the gap between the two lowest rotational-bands predicted by the model. Applied magnetic fields in the 0 -- 8.5 Tesla range confirm the magnetic origin of the spectrum. The temperature and field dependence of the energy spectra are discussed.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2005.MAR.V43.1