Enhancement of paramagnetic defects in yttria stabilized zirconia implanted by Cs ion irradiation

Single crystal samples of cubic zirconia stabilized by 9.5 mol% Y2O3 (YSZ) were implanted with 200 KeV Xe ions and 400 KeV Cs ions up to a dose of 5 × 1016 ions/cm2, then annealed at 200, 300, and 400 °C for 1 h isochronously, respectively. Electron paramagnetic resonance (EPR) and cross-sectional transmission electron microscopy were used to study defect structure and radiated damage mechanism. EPR spectra showed the trigonal signal with g∥ = 1.989 and g⊥ = 1.869, which exhibited axial symmetry with 〈1 1 1〉 direction as symmetry axis composed of six-fold-coordinated Zr3+ sites. Peak-to-peak intensity (per unit volume) of Cs-ion irradiated YSZ is as about 150 time as that of Xe-ion irradiated YSZ. This indicated that the concentration of six-fold-coordinated Zr3+ defects produced by Cs-ion irradiation was far more than that of Xe-ion irradiated. The cross-sectional image of the irradiated samples showed that the Cs-ion irradiation in YSZ produced more defect clusters than Xe-ion irradiation. Annealing did not produce any change for EPR signals and indicated six-fold-coordinated Zr3+ defects was stable defect structure below 400 °C.