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Quantum dissipation theory of slow magnetic relaxation mediated by domain-wall motion in one-dimensional chain compound [Mn(hfac)_{2}BNO_{H}}]

A. S. Ovchinnikov·I. G. Bostrem·V. E. Sinitsyn·A. S. Boyarchenkov·N. V. Baranov·K. Inoue
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Abstract

Based on a quantum dissipation theory of open systems, we present a theoretical study of slow dynamics of magnetization for the ordered state of the new molecule-based magnetic complex [Mn(hfac)_{2}BNO_{H}] composed from antiferromagnetically coupled ferrimagnetic (5/2,1) spin chains. Experimental investigations of the magnetization process in pulsed fields have shown that this compound exhibits a metamagnetic AF-FI transition at a critical field in the order of the interchain coupling. A strong frequency dependence for the ac-susceptibility has been revealed in the vicinity of the AF-FI transition and was associated with an AF-FI interface kink motion. We model these processes by a field-driven domain-wall motion along the field-unfavorable chains correlated with a dissipation effect due to a magnetic system-bath coupling. The calculated longitudinal magnetization has a two-step relaxation after the field is switched off and are found in good agreement with the experiment. The relaxation time determined from the imaginary part of the model ac-susceptibility agrees qualitatively with that found from the remanent magnetization data.

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A. S. Ovchinnikov, I. G. Bostrem, V. E. Sinitsyn, A. S. Boyarchenkov, N. V. Baranov, K. Inoue. 2006-11-23. Quantum dissipation theory of slow magnetic relaxation mediated by domain-wall motion in one-dimensional chain compound [Mn(hfac)_{2}BNO_{H}}]. https://doi.org/10.1103/physrevb.74.174427

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