Ion beam induced cubic to monoclinic phase transformation of nanocrystalline yttria

• Nanocrystalline yttria synthesized by low temperature sol gel method.
• 120 MeV Ag ion induced phase transformation from cubic to monoclinic crystal structure.
• XRD shows monoclinic lattice plane (402¯).
• Raman spectroscopy confirmed the monoclinic mode vibrations.
• HR-TEM confirmed the damaged in Y2O3 lattice under SHI irradiation.

Sol gel derived nanocrystalline yttria pellets are irradiated with 120 MeV Ag9+ ions for fluence in the range 1 × 1012–3 × 1013 ions cm−2. Pristine and irradiated samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. XRD pattern of pristine Y2O3 nanocrystal reveal cubic structure. A new XRD peak at 30.36° is observed in pellet irradiated with 1 × 1013 ions cm−2. The peak at 30.36° is corresponding to (402¯) plane of monoclinic phase. The diffraction intensity of (402¯) plane increases with Ag9+ ion fluence. Raman spectrum of pristine pellet show bands corresponding to cubic phase. And, ion irradiated sample show new peaks at 410, 514 and 641 cm−1 corresponding monoclinic phase. HR-TEM and SAED pattern of ion irradiated sample confirmed the presence of monoclinic phase. Hence, it is confirmed that, 120 MeV Ag9+ ions induce phase transformation in nanocrystalline Y2O3.