Europhys. Lett, 44 (6), pp. 778-782 (1998)
Submillimeter spectroscopy of -Ac magnetic clusters
A. A. Mukhin 1, V. D. Travkin 1, A. K. Zvezdin 1,
S. P. Lebedev 1
A. Caneschi 2 and D. Gatteschi 2
1 General Physics Institute of RAS - 38, Vavilov st., 117942
2 Dipartimento di Chimica, Università di Firenze
Via Maragliano 77, 50144 Firenze, Italy
(received 3 August 1998; accepted in final form 23 October 1998)
PACS. 76.30 - Electron paramagnetic resonance
PACS. 75.10Dg - Crystal-field theory and spin Hamiltonians.
PACS. 75.30Gw - Magnetic anisotropy.
Transitions inside the ground S= 10 multiplet of magnetic clusters Mn12-Ac have been observed in submillimeter transmission spectra measured by means of a quasi-optical backward-wave-oscillator technique in the frequency range -. The temperature dependence of the resonance frequencies, linewidths and mode contributions to the magnetic permeability in the range T=3-35 K are consistent on the whole with a spin S=10 ground state split by a tetragonal crystal field. However, some deviations between the calculated and observed mode contributions at high temperatures suggest the presence of other Mn12-Ac excited multiplets with .