N. SHANNON – 21 MAI

Abstract :

Frustrated magnetism is in many ways a happy accident. Magnets with competing, or frustrated, interactions are ubiquitous amoung oxides materials, including the minerals which make up the earth’s crust. This competition works to supress, and in some cases to eliminate, conventional forms of magnetic order described by Landau theory, along with the excitations, such as spin waves, which accompany them. None the less, it is often possible to measure the properties of these systems with great precision, and to accurately model their magnetic degrees of freedom. For this reason, frustrated magnets, like Helium before them, offer the opportunity to study fundamental questions of many-body physics in a controlled experimental context. Foremost in this effort has been the search for novel phases of matter, and the exotic excitations which characterise them, fuelled by a steady stream of new materials.
Ih this talk a present a brief overvew of some of the topics currently under discussion, including the hunt for quantum spin liquids in two and three dimensions; magnetic analogues of topological insulators; and the possible first observation of spin-nematic order in high magnetic field.