Effect of 120 MeV Au9+ ion irradiation on structural, optical and dielectric properties of YCa4O(BO3)3 nonlinear optical crystal

Yttrium calcium oxy borate (YCOB) is an important nonlinear optical (NLO) crystal belongs to RECOB (RE = Gd, Sm, Nd, Er, La and Y) family of crystals with the general formula RECa4O(BO3)3. YCOB is a negative biaxial crystal which crystallizes in the monoclinic structure with non-centrosymmetric space group Cm. In the present work, the flux grown YCOB single crystals were irradiated with various fluences of 120 MeV Au9+ heavy ions at ambient and at liquid nitrogen (LN2) temperatures, respectively. Grazing incidence angle X-ray diffraction (GIXRD) studies of pristine and irradiated crystals confirm the ion induced surface modification. UV–Visible spectral analysis shows that there was a red shift of optical edge of the pristine sample with ion fluence from 1011 to 1013 ions/cm2. Laser Raman spectrum of YCOB crystal presents the intense band of (BO3)3− modes at 1123 cm−1 and its peak intensity reduces with ion fluence. The dielectric loss and relative permittivity of YCOB crystal show a marked increase with ion irradiation fluence.

► Yttrium calcium oxy-borate crystals were irradiated with 120 MeV Au9+ ions.
► Irradiation was carried out at both ambient and liquid nitrogen temperatures.
► Effects of irradiation on the crystal were analyzed through various studies.
► All studies reveal that surface level modification has been created by Au9+ ions.
► The radiation induced effects are less pronounced at liquid nitrogen temperature.