\n Frustrated mag netism has become an extremely active field of research. The concept of ge ometrical frustration dates back to Wannier&rsquo\;s 1950 study of Ising a ntiferromagnet on the triangular lattice. This simple system illustrates m any defining characteristics of a highly frustrated magnet\, including a m acroscopic ground-state degeneracy and the appearance of power-law correla tions without criticality. In this talk I will discuss a simple generaliza tion of the triangular Ising model\, namely\, a finite number of verticall y stacked triangular layers. Our extensive numerical simulations reveal a low temperature reentrance of two Berezinskii-Kosterlitz-Thouless transiti ons. In particular\, I will discuss how short-distance spin-spin correlati ons can be enhanced by thermal fluctuations\, a phenomenon we termed stiff ness from disorder. This is a generalization of the well-known order-by-di sorder mechanism in frustrated magnets. I will also present an effective f ield theory that quantitatively describes the low-temperature physics of t he multilayer triangular Ising antiferromagnet.

\n DTSTART:20150206T203000Z LOCATION:Physics Building\, Room 204 SUMMARY:Stiffness from disorder in frustrated quasi-two-dimensional magnets END:VEVENT END:VCALENDAR