Exact eigenstates of highly frustrated spin lattices probed in high fields
Abstract
Strongly frustrated antiferromagnets such as the magnetic molecule {Mo72Fe30}, the kagome, or the pyrochlore lattice exhibit a variety of fascinating properties like low-lying singlets, magnetization plateaus as well as magnetization jumps. During recent years exact many-body eigenstates could be constructed for several of these spin systems. These states become ground states in high magnetic fields, and they also lead to exotic behavior. A key concept to an understanding of these properties is provided by independent localized magnons. The energy eigenvalue of these n-magnon states scales linearly with the number n of independent magnons and thus with the total magnetic quantum number M=Ns-n. In an applied field this results in a giant magnetization jump which constitutes a new macroscopic quantum effect. It will be demonstrated that this behavior is accompanied by a massive degeneracy, an extensive (T=0)-entropy, and thus a large magnetocaloric effect at the saturation field. The connection to flat band ferromagnetism will be outlined.
Keywords
Cite
@article{arxiv.cond-mat/0606401,
title = {Exact eigenstates of highly frustrated spin lattices probed in high fields},
author = {J. Schnack and H. -J. Schmidt and A. Honecker and J. Schulenburg and J. Richter},
journal= {arXiv preprint arXiv:cond-mat/0606401},
year = {2007}
}
Comments
4 pages, submitted to the proceedings of the Yamada Conference LX on Research in High Magnetic Fields, August 16-19, 2006 Sendai, Japan