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Observation of the distribution of molecular spin states by resonant quantum tunneling of the magnetization

W. Wernsdorfer·T. Ohm·C. Sangregorio·R. Sessoli·D. Mailly·C. Paulsen
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Abstract

Below 360 mK, Fe magnetic molecular clusters are in the pure quantum relaxation regime and we show that the predicted square-root time relaxation is obeyed, allowing us to develop a new method for watching the evolution of the distribution of molecular spin states in the sample. We measure as a function of applied field H the statistical distribution P(ξ_H) of magnetic energy bias ξ_H$ acting on the molecules. Tunneling initially causes rapid transitions of molecules, thereby digging a hole in P(ξ_H) (around the resonant condition ξ_H = 0). For small initial magnetization values, the hole width shows an intrinsic broadening which may be due to nuclear spins.

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W. Wernsdorfer, T. Ohm, C. Sangregorio, R. Sessoli, D. Mailly, C. Paulsen. 1999-01-26. Observation of the distribution of molecular spin states by resonant quantum tunneling of the magnetization. https://doi.org/10.1103/physrevlett.82.3903

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