Effect of L-alanine, Mn(II) and glycine dopants on the structural, crystalline perfection, second harmonic generation (SHG), dielectric and mechanical properties of BTCA single crystals V. Ganesh a , T. Bhaskar Rao c , K. Kishan Rao c , G. Bhagavannarayana d , Mohd. Shkir b, d, * a Department of Physics, Ganapathy Engineering College, Warangal 506005, India b Department. of Physics, Atma Ram Sanatan Dharma (ARSD) College, University of Delhi, New Delhi 110021, India c Department of Physics, Kakatiya University, Warangal 506009 India d CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012, India highlights < The strong effect on crystalline perfection was found in BTCA crystals due to glycine doping. < The SHG efficiency was found to be higher in case of glycine doped BTCA crystals. < The hardness value was found to be increase with doping. article info Article history: Received 24 December 2011 Received in revised form 17 July 2012 Accepted 8 September 2012 Keywords: A. Optical materials B. Crystal growth C. Mechanical testing C. Raman spectroscopy and scattering D. Defects D. Dielectric properties D. Optical properties abstract Bis thiourea cadmium acetate (BTCA) single crystals were grown at room temperature with different dopants by aqueous solution technique. The crystal system of the grown crystals with all the dopants was confirmed by powder X-ray diffraction study which confirms that there is no extra phase due to doping of L-alanine (LA), Mn(II) and glycine (Gly). It was further confirmed by FT-IR as well as FTeRaman spectroscopy analysis. The effect of LA, Mn(II) and Gly doping on the crystalline perfection was assessed by high-resolution X-ray diffractometry (HRXRD) analysis which revealed that the grown crystals with Gly doping are more perfect in comparison of other dopants. The SHG efficiency was measured using the Kurtz powder technique and shows that the grown crystals with Gly doping are more efficient in comparison of other dopants which is in tune with crystalline perfection. The low values of dielectric constant and loss also revealed that the grown crystals are defect free. The hardness values were found to be increased by increasing the doping concentration. Ó 2012 Elsevier B.V. All rights reserved. 1. Introduction Most of the semiorganic nonlinear optical (SNLO) materials have potential applications in second harmonic generation (SHG), optical storage, optical communication, photonics, electroeoptical modu- lation, optical parametric amplification etc. [1,2]. Semiorganic materials are metaleorganic coordination compounds in which organic ligand plays a dominant role in the nonlinear optical (NLO) effect [3]. For the metallic part, the focus is on group IIB materials (Zn, Cd, and Hg) as these compounds have a high SHG efficiency because the metal center is engaged in p-bonding with the organic ligating groups [4,5]. Metaleorganic complex crystals have over the years been subjected to extensive investigation by several researchers for their wide variety of properties [6,7]. Among these complexes, Bis thiourea cadmium acetate (BTCA) is the simplest NLO crystal whose SHG efficiency is superior to KDP crystal [8]. Dopants are playing the vital role in enhancing the various properties of materials like their single crystal growth rate [9] and many important physical properties like optical transparency [10,11], second harmonic generation (SHG) efficiency [12], etc. Therefore it is essential to transform the structural, optical, physical and electrical properties of these materials either by adding some functional groups [13] or incorporation of dopants [12,14e16], for tailor made applications. * Corresponding author. Department of Physics, Atma Ram Sanatan Dharma (ARSD) College, Universityof Delhi, New Delhi 110021, India. Tel.: þ91 9911769335; fax: þ91 1124111390. E-mail address: shkirphysics@gmail.com (Mohd. Shkir). Contents lists available at SciVerse ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys 0254-0584/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.matchemphys.2012.09.021 Materials Chemistry and Physics 137 (2012) 276e281