Magnetic order in the frustrated magnet Cu5(VO4)2O2CsCl

We propose to use WISH to characterise magnetic order of a new quantum (S=1/2) geometrically frustrated material based on the mineral averievite, Cu_5(VO_4)_2O_2CsCl. This material has a magnetic lattice based on the pyrochlore slab (a kagome lattice sandwiched by two Cu^2+ hexagonal lattices) and undergoes a magnetic transition at 20 K despite strong antiferromagnetic exchange (Th_W = -190 K). We propose to use the high-intensity instrument WISH to observe magnetic scattering below the transition and in the superparamagnetic regime.