| Abstract Scope |
High entropy oxides (HEOs) have attracted significant scientific interest due to their compositional complexities unlocking novel or enhanced properties. The incorporation of multiple elements into a cation lattice site in HEOs influences atomic-level responses to irradiation. This study investigates nanoscale phase transitions in perovskite-structured Sr(Zr₀.₂Sn₀.₂Ti₀.₂Hf₀.₂Nb₀.₂)O₃ (Sr-HEO) under swift heavy ion irradiation (774 MeV Xe). Unlike typical amorphous ion-tracks, Sr-HEO exhibits discontinuous and partially recrystallized tracks. The presence of multiple cations at the B-site reduces ion track diameters compared to SrTiO₃ under the same energy-loss conditions. While SrTiO₃ tracks display a core-shell structure with a disordered interface, Sr-HEO tracks exhibit minimal lattice distortion, restricted within ~2–3 monolayers. Atomic-resolution observations reveal that the amorphous phase in Sr-HEO remains stable under electron irradiation, unlike SrTiO₃, which readily recrystallizes. This stability is attributed to structural complexities resisting recrystallization, outweighing electron-induced excitations and local heating effects that facilitate defect migration in SrTiO₃. |