The phenomenon of magnetic frustration can lead to a rich variety of interesting physical behaviour. Often this frustration has a geometric origin and materials that are constructed from geometrically frustrated networks of magnetic ions, such as the antiferromagnetic kagome lattice of corner-sharing triangles, can evade conventional long range magnetic order at low temperatures as a result of competing exchange interactions. Materials that combine strong magnetic frustration with low spin magnetic ions are particularly fascinating since they are believed to support exotic quantum spin liquid ground states. In this talk, I will present new vanadium based oxyfluoride materials that consist of kagome layers of V 4+ S = ½ cations and describe how our experimental study of these materials reveals some important clues regarding the nature of the quantum spin liquid state of the S = ½ kagome antiferromagnet .
 L. Clark et al. , Phys. Rev. Lett. 110 , 207208 (2013).