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arXiv · cond-mat/9902218

Non-Kramers Freezing and Unfreezing of Tunneling in the Biaxial Spin Model

E. M. Chudnovsky·X. Martinez-Hidalgo
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Abstract

The ground state tunnel splitting for the biaxial spin model in the magnetic field, H = -D S_{x}^2 + E S_{z}^2 - g μ_B S_z H_z, has been investigated using an instanton approach. We find a new type of spin instanton and a new quantum interference phenomenon associated with it: at a certain field, H_2 = 2SE^{1/2}(D+E)^{1/2}/(g μ_B), the dependence of the tunneling splitting on the field switches from oscillations to a monotonic growth. The predictions of the theory can be tested in Fe_8 molecular nanomagnets.

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E. M. Chudnovsky, X. Martinez-Hidalgo. 2000-07-11. Non-Kramers Freezing and Unfreezing of Tunneling in the Biaxial Spin Model. https://doi.org/10.1209/epl%2Fi2000-00282-0

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