Oxygen miscibility gap and spin glass formation in the pyrochlore Lu2Mo2O7

The cubic Lu2Mo2O7−x system exhibits a miscibility gap between coexisting pyrochlore phases at 1600 °C. Neutron powder diffraction refinement and chemical analysis shows that the gap separates stoichiometric x=0 and oxygen-deficient x≈0.4 phases. Lu2Mo2O7−x has a frustrated spin glass ground state that is sensitive to the oxygen content.