Magnetic structure in the S = 1/2 frustrated pyrochlore slab antiferromagnet Averievite Cu5(VO4)2O2CsCl

The search for quantum spin liquids (QSLs) remains a cornerstone of condensed matter physics. The S = 1/2 kagome Heisenberg magnet (KHM) is considered the most promising model system for the realisation of 2D QSLs. We have synthesised high quality powders of a new S=1/2 KHM averievite and its Zn-doped variants ZnxCu5–x(VO4)2O2CsCl, where x = 0, 1 and 2. We have performed extensive magnetometry, neutron diffraction (exp no. RB1920248) and inelastic neutron scattering (exp no. 4-05-746) measurements on our range of Zn-averievite samples between 0 < x < 2. Our results demonstrate the evolution of magnetic order to disorder with increased Zn doping, towards a potential QSL state in the ideal kagome geometry of x = 2. However, there are three major limitations with the data we have thus far collected due to the fact that the samples are powders: (i) the magnetic structure of x=0 cannot be uniquely refined; (ii) the spin waves of x=0 cannot be modelled using linear spin wave theory to extract exchange parameters; (iii) the powder-averaged Q-dependence of the diffuse excitations for x=2 do not allow confirmation of a QSL state. We will use this experiment to uniquely resolve the magnetic structure for x=0 using single crystal diffraction on WISH. The results will in turn aid the modelling of the spin waves in future inelastic scattering experiments and, ultimately, deepen our understanding of the potential QSL state when x=2.