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Magnetic long-range order induced by quantum relaxation in single-molecule magnets

M. Evangelisti·F. Luis·F. L. Mettes·N. Aliaga·G. Aromi·J. J. Alonso·G. Christou·L. J. de Jongh
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Abstract

Can magnetic interactions between single-molecule magnets (SMMs) in a crystal establish long-range magnetic order at low temperatures deep in the quantum regime, where the only electron spin-fluctuations are due to incoherent magnetic quantum tunneling (MQT)? Put inversely: can MQT provide the temperature dependent fluctuations needed to destroy the ordered state above some finite Tc, although it should basically itself be a T-independent process? Our experiments on two novel Mn4 SMMs provide a positive answer to the above, showing at the same time that MQT in the SMMs has to involve spin-lattice coupling at a relaxation rate equaling that predicted and observed recently for nuclear spin-mediated quantum relaxation.

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M. Evangelisti, F. Luis, F. L. Mettes, N. Aliaga, G. Aromi, J. J. Alonso, G. Christou, L. J. de Jongh. 2004-02-14. Magnetic long-range order induced by quantum relaxation in single-molecule magnets. https://doi.org/10.1103/physrevlett.93.117202

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