06-228 Marek Biskup, Lincoln Chayes, Steven A. Kivelson
On the absence of ferromagnetism in typical 2D ferromagnets (144K, PDF) Aug 21, 06
Abstract , Paper (src), View paper (auto. generated pdf), Index of related papers

Abstract. We consider the Ising systems in $d$ dimensions with nearest-neighbor ferromagnetic interactions and long-range repulsive (antiferromagnetic) interactions which decay with a power, $s$, of the distance. The physical context of such models is discussed; primarily this is $d=2$ and $s=3$ where, at long distances, genuine magnetic interactions between genuine magnetic dipoles are of this form. We prove that when the power of decay lies above $d$ and does not exceed $d+1$, then for all temperatures, the spontaneous magnetization is zero. In contrast, we also show that for powers exceeding $d+1$ (with $d\ge2$) magnetic order can occur.

Files: 06-228.src( 06-228.comments , 06-228.keywords , ferromagnet-submit.pdf.mm )