Spin tunneling in molecular magnets has attracted much attention, however theoretical considerations of this phenomenon up to now have not taken into account the many-spin nature of molecular magnets. We present, to our knowledge, the first successful attempt of a realistic calculation of tunneling splittings for Mn12 molecules, thus achieving a quantitatively accurate many-spin description of a real molecular magnet in the energy interval ranging from about 100 K down to 10−12 K. Comparison with the results of the standard single-spin model shows that many-spin effects affect the tunneling splittings considerably. The values of ground state splitting given by single-spin and many-spin models differ from each other by a factor of five.
@article{arxiv.cond-mat/9909278,
title = {Many-Spin Effects and Tunneling Properties of Magnetic Molecules},
author = {M. Al-Saqer and V. V. Dobrovitski and B. N. Harmon and M. I. Katsnelson},
journal= {arXiv preprint arXiv:cond-mat/9909278},
year = {2009}
}