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The European Physical Journal B
ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)
Abstract Volume 4 Issue 2 (1998) pp 223-231
Magnetic quantum coherence in trigonal and hexagonal systems
J.-L. Zhu (1)(3), R. Lü (1)(3) (a), X.-B. Wang (2), X. Chen (3), L. Chang (3), F.-C. Pu (4)
(1) CCAST (World Laboratory), P.O. Box 8730, Beijing 100080, P.R. China
(2) Center for Advanced Study, Tsinghua University, Beijing 100084, P.R. China
(3) Department of Physics, Tsinghua University, Beijing 100084, P.R. China
(4) Department of Physics, Guangzhou Normal College, Guangzhou 510400, P.R. China and Institute of Physics, Academia Sinica, P.O. Box 603-99, Beijing 100080, P.R. China
Received: 18 November 1997 / Revised: 18 March 1998 / Accepted: 6 April 1998
Abstract: The tunneling behaviors of the magnetization vector are studied in ferromagnetic systems with trigonal and hexagonal crystal symmetries, respectively. The Euclidean transition amplitudes between the energetically degenerate easy directions are evaluated with the help of the dilute instanton-gas approximation. By using the effective Hamiltonian method, the ground-state tunneling level splittings are clearly shown for each kind of symmetry and are found to depend on the parity of the total spin of the ferromagnetic particle. The effective Hamiltonian method is demonstrated to be equivalent to the dilute instanton-gas approximation. Possible relevance to experiments is discussed.
PACS. 73.40.Gk Tunneling[:AND:] 75.10.Jm Quantized spin models - 75.45.+j Macroscopic quantum phenomena in magnetic systems
(a) email: rlu@Phys.Tsinghua.edu.cn
Article in PDF-Format (355 KB)
Online publication: August 10, 1998
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