Available online at www.scholarsresearchlibrary.com Scholars Research Library Archives of Physics Research, 2010, 1 (2): 1-7 (http://scholarsresearchlibrary.com/archive.html) ISSN 0976-0970 1 Scholar Research Library Electrical, Mechanical, Thermal and nonlinear optical properties of pure and doped L-Threonine acetate single crystals T. Sujatha 1 , P. Praveen Kumar 2 , J. Merline Shyla 1 and J. Madhavan 1 1 Department of Physics, Loyola College, Chennai, India 2 Department of Physics, Presidency College, Chennai, India ______________________________________________________________________________ Abstract In the present investigation, influence of metal (Cu 2+ and Mg 2+ ) dopant on the Electrical, Mechanical, Thermal and nonlinear optical properties of pure LTA crystals has been studied systematically. The exact weight percentage of the Cu 2+ and Mg 2+ present in doped crystals were determined by Atomic Absorption Studies. Single crystal X-ray diffraction studies were carried out for the pure and doped crystals. Dielectric and photoconductivity studies were carried out for the grown crystals. Mechanical and thermal stability of the grown crystals are determined by Vickers microhardness and thermal studies. Nonlinear optical properties were studied by SHG studies. Keywords: Electrical studies, Mechanical studies, Thermal studies, NLO, LTA. ______________________________________________________________________________ INTRODUCTION Nonlinear optical (NLO) organic crystals with high conversion efficiencies are required for optical second harmonic generation (SHG) owing to their practical applications in the domain of optoelectronics and photonics [1, 2]. Aminoacid family crystals are of great interest due to their attracting nonlinear optical properties [3–4]. In recent years, more promising NLO materials with better properties have been discovered and studied. Amino acid L-threonine acetate (LTA) crystal has been reported as a promising NLO material with SHG efficiency higher than that of KDP, and can be used for the fabrication of optoelectronic devices [5]. In the present study, influence of metal (Cu 2+ and Mg 2+ ) dopant on the Electrical, Mechanical, Thermal and nonlinear optical properties of pure LTA crystals has been carried out. Pure and doped LTA crystals are grown by slow evaporation solution growth technique. Good quality, transparent and defect free tiny crystals were formed due to spontaneous nucleation. The same procedure was adopted to grow doped LTA crystals with the addition of 2 mol % of Cu 2+ and Mg 2+ into the respective solution. Single crystal XRD studies were carried out, and it is observed from the XRD that both pure and doped LTA belongs to orthorhombic structure with