Microstructural evolution of the pyrochlore compound Er2Ti2O7 induced by light ion irradiations

In this report, we present results of an irradiation damage study on a pyrochlore compound, Er2Ti2O7. Polycrystalline Er2Ti2O7 was irradiated with 400 keV Ne2+ ions at cryogenic temperature (∼77 K) to fluences ranging from 2 × 1018 to 2 × 1019 ions/m2. Irradiation-induced microstructural evolution was examined using grazing incidence X-ray diffraction (GIXRD) at angles of γ = 0.25° and 3°. It was found that the irradiated Er2Ti2O7 undergoes significant lattice swelling before succumbing to a radiation-induced partial amorphization transformation. Both of the extent of the lattice swelling and the lattice disorder of the Er2Ti2O7 increase with increasing Ne ion fluence prior to partial amorphization. We present here a detailed discussion regarding the nature of the defects responsible for the observed lattice swelling and disorder in Er2Ti2O7.