Europhys. Lett.
Volume 60, Number 2, October 2002
Page(s) 302 - 308
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 October 2002
DOI: 10.1209/epl/i2002-00357-4

Europhys. Lett., 60 (2) , pp. 302-308 (2002)

Quantum tunneling in molecular ferric wheels

O. Waldmann

Physikalisches Institut III, Universität Erlangen-Nürnberg D-91058 Erlangen, Germany

(Received 7 January 2002; accepted in final form 5 August 2002)

An effective spin Hamiltonian is presented which describes the low-lying energy spectrum of antiferromagnetic molecular rings with high accuracy. It will be shown that for the particular case of the ferric wheels, quantum coherent phenomena are best discussed in terms of resonant quantum tunneling of the spin vector between different rotational modes. These quantum processes are associated to anticrossings of higher-lying spin multiplets with $\Delta S = 2$.

75.10.Jm - Quantized spin models.
75.50.Xx - Molecular magnets.
73.40.Gk - Tunneling.

© EDP Sciences 2002