Calculations of the onset temperature for tunneling in multispin systems
https://doi.org/10.17586/2220-8054-2017-8-4-454-461
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 Mn4 group is presented and the result found to be in excellent agreement with reported experimental measurements.
Supporting agencies: This work was supported by the Icelandic Research Fund and the Academy of Finland (grant 278260) and partially financially supported by the Government of the Russian Federation (grant 074-U01)
About the Authors
S. M. Vlasov
ITMO University; Univ. of Iceland
Russian Federation
Russian Federation
Science Institute and Faculty of Physical Sciences
197101; Kronverkskiy, 49; St. Petersburg; 107 Reykjav´ık; Iceland
P. F. Bessarab
ITMO University; Univ. of Iceland
Russian Federation
Russian Federation
Science Institute and Faculty of Physical Sciences
197101; Kronverkskiy, 49; St. Petersburg; 107 Reykjav´ık; Iceland
V. M. Uzdin
ITMO University; St. Petersburg State University
Russian Federation
Russian Federation
197101; Kronverkskiy, 49; 198504; St. Petersburg
H. J´onsson
Univ. of Iceland; Aalto University
Russian Federation
Russian Federation
Science Institute and Faculty of Physical Sciences; Department of Applied Physics
107 Reykjav´ık; Iceland; FIN-00076; Espoo; Finland
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Review
For citations:
Vlasov S.M., Bessarab P.F., Uzdin V.M., J´onsson H. Calculations of the onset temperature for tunneling in multispin systems. Nanosystems: Physics, Chemistry, Mathematics. 2017;8(4):454-461. https://doi.org/10.17586/2220-8054-2017-8-4-454-461
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