Calculations of the onset temperature for tunneling in multispin systems

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2017
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Mcode
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Language
en
Pages
454-461
Series
Nanosystems: Physics, Chemistry, Mathematics, Volume 8, issue 4
Abstract
Transitions between magnetic states of a system coupled to a heat bath can occur by exceeding the energy barrier, but as temperature is lowered quantum mechanical tunneling through the barrier becomes the dominant transition mechanism. A method is presented for estimating the onset temperature for tunneling in a system with an arbitrary number of spins using the second derivatives of the energy with respect to the orientation of the magnetic vectors at the first order saddle point on the energy surface characterizing the over-the-barrier mechanism. An application to a monomer and a dimer of molecular magnets containing a Mn 4 group is presented and the result found to be in excellent agreement with reported experimental measurements.
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Keywords
magnetic transitions, tunneling, rate theory, molecular magnet
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Citation
Vlasov , S M , Bessarab , P F , Uzdin , V M & Jonsson , H 2017 , ' Calculations of the onset temperature for tunneling in multispin systems ' , Nanosystems: Physics, Chemistry, Mathematics , vol. 8 , no. 4 , pp. 454-461 . https://doi.org/10.17586/2220-8054-2017-8-4-454-461