A comparative study of ferroelectric triglycine sulfate (TGS) crystals grown by conventional slow evaporation and unidirectional method

Unidirectional 〈0 1 0〉 TGS single crystal of diameter 35 mm and length 80 mm was grown by Sankaranarayanan–Ramasamy (SR) method. Nearly two times higher d33 value has been obtained for the SR grown TGS crystal compared to conventional grown TGS. The etch pit density of SEST and SR method grown TGS crystal is 2.1 × 102 cm−2 and 1.5 × 102 cm−2 respectively. The values of hardness were found to be 152 kg/mm2 for SR grown TGS and 108 kg/mm2 for SEST grown TGS crystal. The average laser damage threshold obtained on the SEST grown TGS crystal was 29 mJ/cm2 whereas a high damage threshold of 39 mJ/cm2 was obtained for the SR grown crystal. The SR method grown TGS has 5% higher transmittance as against conventional method grown crystal. Dielectric study showed higher dielectric permittivity and lower dielectric loss in SR grown TGS crystal.

(a) TGS crystal grown by conventional method and (b) Cut and polished ingots of b-axis TGS crystals grown by unidirectional method.Figure optionsDownload as PowerPoint slideHighlights
► 〈0 1 0〉 directed TGS single crystal was grown by Sankaranarayanan–Ramasamy method which has the sizes of 80 mm length and 35 mm diameter for the first time.
► The conventional and SR-grown TGS crystals were characterized using piezoelectric, etching, microhardness, LDT, UV-transmittance and dielectric analysis.
► The SR-grown TGS crystal has higher piezoelectric-d33 co-efficient, microhardness, LDT, optical transparency, dielectric permittivity and lower EPD, dielectric loss than the crystal grown by conventional method.
► The major reason for higher crystalline quality in SR-grown crystal was discussed.