Multiple nearest-neighbor exchange model for the frustrated magnetic molecules Mo72Fe30 and Mo72Cr30
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.
Cite
@article{arxiv.0801.2065,
title = {Multiple nearest-neighbor exchange model for the frustrated magnetic molecules Mo72Fe30 and Mo72Cr30},
author = {Christian Schröder and Ruslan Prozorov and Paul Kögerler and Matthew D. Vannette and Xikui Fang and Marshall Luban and Akira Matsuo and Koichi Kindo and Achim Müller and Ana Maria Todea},
journal= {arXiv preprint arXiv:0801.2065},
year = {2009}
}
Comments
8 pages, 5 figures