Abstract
We present static and dynamical magnetic properties of a new organic cluster compound, Mn12Ac. High field magnetization and susceptibility data indicate that the clusters have a S=10 ground state with a high anisotropy and are magnetically well isolated from each other. Low temperature specific heat results are in agreement with this picture. Those properties make this system ideal to study superparamagnetic relaxation and possible quantum effects at the nanoscopic scale at very low temperatures. Above 4K the relaxation times follow an Arrhenius law \( \tau = {\tau _o}{e^{\Delta /k}}{_b^T} \) with Δ/kb~64 K, in agreement with high field magnetization, and τO~10-7 S. AC susceptibility data under dc field show a new and unexpected field dependence of the relaxation time that seems to indicate that thermally activated Quantum Tunneling of the Magnetization through the anisotropy energy barrier occurs.
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Novak, M.A., Sessoli, R. (1995). AC Susceptibility Relaxation Studies on a Manganese Organic Cluster Compound: Mn12Ac. In: Gunther, L., Barbara, B. (eds) Quantum Tunneling of Magnetization — QTM ’94. NATO ASI Series, vol 301. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-0403-6_10
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DOI: https://doi.org/10.1007/978-94-011-0403-6_10
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