Advanced characterization technique for mechanochemically synthesized materials: neutron total scattering analysis

Local order of orthorhombic weberite-type Y3TaO7 as determined by neutron total scattering and density functional theory calculations✰

“…Analysis of neutron total scattering revealed that the local atomic arrangement is nearly identical in both amorphous and disordered pyrochlore oxides and can be best described by a weberite-type structural model [8]. Intriguingly, this weberite-type atomic arrangement also has been reported for pyrochlore compositions disordered by a variety of other methods including high-temperature treatment, high-energy ball milling [9], chemical doping, or deviation from ideal stoichiometry [10]. As this weberite-type configuration appears to be a general phenomenon in disordered pyrochlore, there has recently been an increased interest [11] in oxide materials that exhibit the weberite-type structure over all length-scales.…”

Disorder in Ho2Ti2−xZrxO7: pyrochlore to defect fluorite solid solution series

“…48 Random averaging of weberite-type local congurations leads to a long-range disordered, defect uorite structure when averaged over many unit cells. 44,46 Heterogeneous disordering processes with different short-and longrange structural motifs have been similarly observed for other ceramics, such as spinel, 49 and different disordering processes through intrinsic (nonstoichiometry and chemical composition 15,50 ) and extrinsic (ball milling and irradiation 43,51 ) means. This behavior is consistent with Pauling's rules which have been shown to dictate the local atomic arrangements in disordered ceramics.…”

“…The trend of DH mix is very similar in shape and magnitude to those reported for the aforementioned binary oxide solid solutions. [50][51][52][53][54][55] This behavior was attributed to the formation of ordered nanoscale clusters involving cations, oxygen, and oxygen vacancies. [52][53][54][55][56][57] A t of the DH mix data was produced by calculating DH mix values from the quadratic t of DH ds using eqn (7).…”

Predicting short-range order and correlated phenomena in disordered crystalline materials

“…While we have shown the examples of the behavior of spinel and pyrochlore structures, we have experimental data that show the same behavior for doped ThO 2 , A 2 BO 5 oxides, and A 3 BO 7 oxides. Furthermore, this complexity has been observed in materials disordered by nonstoichiometry ( 43 ), intense radiation ( 10 ), mechanochemical synthesis ( 44 ), or temperature exposure ( 45 ). This demonstrates that the new disordering concept presented in this study is, as Pauling’s rules were for ordered ionic compounds, a general phenomenon for a wide range of disordered materials independent on how the disorder is introduced.…”