ion beam induced cubic to monoclinic phase transformation of nanocrystalline yttria
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 ?40 2? plane of monoclinic phase. the diffraction intensity of ?40 2? 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.
recently nanocrystalline yttrium oxide (y2o3) attracted extensive research interest due to its unique optical, electrical, chemical and thermal properties. y2o3 finds wide usage in a many luminescent host materials, medical diagnostics as well as biological, industrial and research fields [1–3]. cubic phase of y2o3 exhibit wide transparent range from uv (220 nm) to infrared ( 8 lm) region, it is optically isotropic and hard, having high refractive index ( 1.92). it possess high corrosion resistivity, high radiation stability, high melting point ( 2723 k), large band gap (5.72 ev) and low phonon energy ( 380 cm 1) which leads to very narrow emission and enhanced quantum efficiency [4,5].
