COLLOQUIUM: Frustrated Magnetic Pyrochlores -- a Rich Playground for the Study of Exotic Collective Phenomena
(University of Waterloo and Canadian Institute for Advanced Research)
Oskar Klein auditorium ()
Oskar Klein auditorium
Frustration is a ubiquitous phenomenon in condensed matter physics,
and in science in general.
One can even read about it on Wikipedia:
In simple terms, frustration arises when a system cannot minimize
its total classical ground state energy by minimizing the
energy between interacting degrees of freedom, pair by pair.
There has been in recent years an explosion of experimental and theoretical
activities directed at the study of geometrically frustrated magnetic
systems. The motivation stems from the hope that highly frustrated
magnetic systems may give rise to exotic quantum and classical phenomena.
Experimentally, materials where magnetic moments (spins) reside on a
three-dimensional pyrochlore lattice of corner-sharing tetrahedra
have proven to be the host of unusual and intriguing behaviours.
Examples include the spin ice phenomenology, collective paramagnetic
(spin liquid) state, persistent spin dynamics down to absolute zero
temperature and, most recently, topological excitations akin
to magnetic monopoles connected by effective "Dirac strings".
In this talk, I will review the motivation for the search of exotic
phenomena in highly frustrated magnetic systems, and discuss some
of the interesting ones that are being explored in the
magnetic pyrochlore oxide materials.