Propagation of spin information at supra-molecular scale through hetero-aromatic linkers

We report an in-depth study on how spin information propagates at supramolecular scale through afamily of heteroaromatic linkers. By density-functional theory calculations, we rationalize the behavior ofa series of Cr7Ni dimers for which we are able to systematically change the aromatic linker thus tuning thestrength of the magnetic interaction, as experimentally shown by low temperature micro-SQUID andspecific heat measurements. We also predict a cos2 dependence of the magnetic coupling on the twistingangle between the aromatic cycles in bicyclic linkers, a mechanism parallel to charge transport on similarsystems [L. Venkataraman et al., Nature (London) 442, 904 (2006)].