Preparation and electrical conductivity of (Zr, Hf, Pr, Y, La) O high entropy fluorite oxides

Abatract A series of compositionally complex fluorite oxides (CCFOs) were prepared by ball milling the mixture of ZrO 2 , HfO 2 , Y 2 O 3 , La 2 O 3 , and Pr 6 O 11 followed by conventional solid-state sintering. Both XRD and TG-DSC results demonstrated that single-phase (Zr 0.2 Hf 0.2 Pr 0.2 Y 0.2 La 0.2 )O 2-δ was formed at 1400 °C. Elements in bulk ceramic were uniformly distributed without evident accumulation according to SEM-EDS pictures. TEM results revealed that polycrystalline ceramic powder was assignable to cubic Fm-3m fluorite structure. The electrical conductivity ( σ ) was measured via EIS technology and activation energy ( E a ) of CCFOs was calculated in Arrhenius plots. In the temperature range of 300-750 °C, CCFOs preserved the same conduction mechanism and (Zr 0.1667 Hf 0.1667 Pr 0.1667 Y 0.25 La 0.25 )O 2-δ possessed higher σ and lower E a than other high entropy fluorite oxides which is related to the incorporation of Pr element or the connection of cation-V o complex.