Magnetic correlations in the locally not-quite-fluorite nor pyrochlore rare-earth zirconates RE2Zr2O7

The rare-earth pyrochlore oxides A2B2O7 have been extensively studied due to the observation of unconventional electronic and magnetic ground-states due to geometric frustration.The heavier-rare earth zirconates (RE2Zr2O7, with Z > Gd) crystallise in a more-disordered defect-fluorite structure, when probed by diffraction methods. Recently, local and short-range-order probes have identified a smooth-continuous increase in disorder when moving through the zirconate series from pyrochlore to defect-fluorite members. We plan to use GEM to generate neutron-PDFs for detailed interrogation of the local structure evolution through the series, as well to measure magnetic-PDFs to investigate magnetic correlations in the spin-glass ground-states of the Er2Zr2O7 and Yb2Zr2O7. Previously, the magnetic properties of this end of the zirconate series has been significantly under-studied.