Atomic order-disorder engineering in the La2Zr2O7 pyrochlore under low energy ion irradiation

Cation and anion disordering affect the structural and electronic properties of the isometric A2B2O7 pyrochlore materials. Here, we report a study on the structural response of La2Zr2O7 at two different temperatures (300 K and ~88 K) as a function of ion fluence (1 × 1013, 5 × 1013, and 1 × 1014 ions/cm2). The effect of ion fluence and irradiation temperature on the structural properties have been investigated using the grazing angle x-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy. GIXRD results confirmed that the weakening/broadening of the diffraction peaks and lattice volume expansion increases monotonically as a function of ion fluence at both the temperatures and are more pronounced at ~88 K. The cation and anion disordering appear to be ion fluence and irradiation temperature-dependent. Raman spectroscopy shows that the atomic disordering is more pronounced with enhanced ion fluence and revealed the involvement of the X48f parameter in the enhancement of disordering in the system. The HRTEM analysis revealed that the deterioration in the atomic ordering (amorphization) is significantly more pronounced at ~88 K. The qualitative analysis of cation/anion disordering and structural deformation revealed that irradiation parameters play a crucial role in developing and altering the properties of the pyrochlore materials for the technological applications.