The electrical, magnetic, and structural properties of Sr3(Ru1−xMnx)2O7 (0 ≤x≤ 0.2) are investigated. The parent compound Sr3Ru2O7 is a paramagnetic metal, critically close to magnetic order. We have found that, with a Ru-site doping by only a few percent of Mn, the ground state is switched from a paramagnetic metal to an antiferromagnetic insulator. Optical conductivity measurements show the opening of a gap as large as 0.1 eV, indicating that the metal-to-insulator transition is driven by the electron correlation. The complex low-temperature antiferromagnetic spin arrangement, reminiscent of those observed in some nickelates and manganites, suggests a long range orbital order.
@article{arxiv.cond-mat/0509227,
title = {Impurity-induced transition to a Mott insulator in Sr$_3$Ru$_2$O$_7$},
author = {R. Mathieu and A. Asamitsu and Y. Kaneko and J. P. He and X. Z. Yu and R. Kumai and Y. Onose and N. Takeshita and T. Arima and H. Takagi and Y. Tokura},
journal= {arXiv preprint arXiv:cond-mat/0509227},
year = {2009}
}