Structural assessment and irradiation response of La2Zr2O7 pyrochlore: Impact of irradiation temperature and ion fluence

Abstract

State of the art applications (nuclear waste host, scintillators, piezoelectric, SOFCs, etc.) of isometric pyrochlore, A2B2O7, are very sensitive to the structural assessment upon ion irradiation. In the present study, La2Zr2O7 is irradiated using 1 MeV Xe4+ ions with fluence of 1 × 1013, 5 × 1013, and 1 × 1014 ions/cm2 at ~ 88 K and 300 K. The impact of irradiation temperature and ion fluence on the structural properties of the La2Zr2O7 are investigated using the GIXRD, Raman spectroscopy and high resolution transmission electron microscopy (HR-TEM). The GIXRD and Raman results indicate that the degradation of the crystallinity (i.e., damage/amorphization) are significantly higher with enhanced fluence at ~ 88 K than that of 300 K. The induced lattice strain also increases with an increase of ion fluence and it is more pronounced at ~88 K. The HR-TEM results of the La2Zr2O7 samples exhibit that degradation of the atomic ordering are more pronounced at ~ 88 K. The prominent induced strain and degradation of crystallinity (i.e., damage/amorphization) at ~ 88 K appear to be ion fluence and irradiation temperature-dependent. This study is enlightening the effect of the ion fluence and irradiation temperature on the degradation of crystallinity (i.e., damage/amorphization). © 2020 Elsevier B.V.