Multiple nearest-neighbor exchange model for the frustrated magnetic molecules {Mo72Fe30} and {Mo72Cr30}

TitleMultiple nearest-neighbor exchange model for the frustrated magnetic molecules {Mo72Fe30} and {Mo72Cr30}
Publication TypeJournal Article
Year of Publication2008
AuthorsSchroder C, Prozorov R, Kogerler P, Vannette MD, Fang XK, Luban M, Matsuo A, Kindo K, Muller A, Todea AM
Journal TitlePhysical Review B
Date PublishedJun
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberISI:000257289300051
Keywordsfield, state, superconductors

Our measurements of the differential susceptibility partial derivative M/partial derivative H of the frustrated magnetic molecules {Mo72Fe30} and {Mo72Cr30} reveal a pronounced dependence on magnetic field (H) and temperature (T) in the low H-low T regime, contrary to the predictions of the existing models. Excellent agreement with experiment is achieved upon formulating a nearest-neighbor classical Heisenberg model where the 60 nearest-neighbor exchange interactions in each molecule, rather than being identical as has been assumed heretofore, are described by a two-parameter rectangular probability distribution of values of the exchange constant. We suggest that the probability distribution provides a convenient phenomenological platform for summarizing the combined effects of multiple microscopic mechanisms that disrupt the idealized picture of a Heisenberg model based on a single value of the nearest-neighbor exchange constant.

Alternate JournalPhys. Rev. B