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arXiv · 0801.2065

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

Christian Schröder·Ruslan Prozorov·Paul Kögerler·Matthew D. Vannette·Xikui Fang·Marshall Luban·Akira Matsuo·Koichi Kindo·Achim Müller·Ana Maria Todea
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Abstract

Our measurements of the differential susceptibility dM/dH 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 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 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.

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Christian Schröder, Ruslan Prozorov, Paul Kögerler, Matthew D. Vannette, Xikui Fang, Marshall Luban, Akira Matsuo, Koichi Kindo, Achim Müller, Ana Maria Todea. 2008-05-09. Multiple nearest-neighbor exchange model for the frustrated magnetic molecules Mo72Fe30 and Mo72Cr30. https://doi.org/10.1103/physrevb.77.224409

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