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“Hidden” Spin–Spin Interactions in Complex Multispin Solids
Author(s) -
Gorelik Elena V.,
Ovcharenko Victor I.,
Baumgarten Martin
Publication year - 2008
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200701305
Subject(s) - chemistry , spin (aerodynamics) , exchange interaction , k nearest neighbors algorithm , substructure , condensed matter physics , consistency (knowledge bases) , chemical physics , ferromagnetism , thermodynamics , physics , structural engineering , artificial intelligence , computer science , engineering , geometry , mathematics
Abstract A detailed analysis of the electronic structure and magnetic properties of a heterospin network based on a Cu(hfac) 2 complex with a nitronyl nitroxide biradical using the broken‐symmetry density functional theory approach is reported. An extremely complex set of exchange parameters was revealed that cannot be obtained from the data of magnetochemical experiments alone. The compensating contributions from various exchange clusters show themselves in a sophisticated combination, and would be “hidden” without an in‐depth quantum chemical investigation. For this purpose the extended network was subdivided into the dominating spin clusters bridged by the organic biradical spacer and each spin system was checked for a consistency of the spin couplings. Fairly large positive and negative exchange couplings in the strongly coupled clusters were found to cancel each other out. Furthermore, the detailed substructure analysis revealed that even in a linearly aligned spin system the next‐nearest‐neighbor interactions can be of the utmost importance and of similar size to that of the direct‐neighbor exchange. Calculated exchange interaction parameters were employed to model the temperature dependence of the effective magnetic moment for the heterospin system under study. The use of PBE0 estimates of exchange interaction parameters yielded a μ eff ( T ) dependence that was in good agreement with the experimental data, which enabled the data to be used as a starting point in the fitting procedure leading to the physical meaningful results.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)