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

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• 作者：M. Kalidasan^a ; R. Arun Kumar^a ; ^b ; ¹ ; K. Asokan^c ; R. Dhanasekaran^a ; ^{rdhanasekaran@annauniv.edu}
• 关键词：YCOB crystal ; 120&#xA0 ; MeV Au9+ ion ; Irradiation effects ; (BO3)3&minus ; group
• 刊名：Nuclear Instruments and Methods in Physics Research Section B ; Beam Interactions with Materials and Atoms
• 出版年：2012
• 期刊代码：42_0168583x
• 类别：ph
• 出版时间：1 June, 2012
• 卷：280
• 期：Complete
• 页码：134-139
• 文件大小：1360 K

摘要

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鈭?/sup> modes at 1123 cm鈭? 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.}