AFM studies of swift heavy ion and electron irradiated mixed barium strontium borate nonlinear optical crystal

Single crystals of novel nonlinear optical material of mixed barium strontium borate is grown in our laboratory by employing the low-temperature solution technique. Equal proportion (1: 1 molar ratio) of AR grade barium borate and strontium borate are mixed together in double distilled water to prepare a supersaturated solution. The solution is allowed to evaporate at constant temperature (30degreesC) in a Petri dish for about a week which resulted in the formation of seed crystals. These seed crystals are used to grow larger crystals by suspending them using fine silk thread in the supersaturated mother solution. The solution is allowed to evaporate at constant temperature. This resulted in the growth of good transparent crystals of dimension 15 mm x 10 mm x 1 mm after about one month. These crystals show good second harmonic generation (SHG) efficiency. The mixed barium strontium berate crystal is found to be a promising nonlinear optical crystal, which possibly can be used for fabrication of photonic devices. The single crystals of mixed barium strontium berate are irradiated by 120 MeV Ag(+13) swift heavy ions (SHI) of fluence 5 x 10(11) ions/cm at Nuclear Science Centre, New Delhi and also by electrons of 8 MeV energy with a fluence 5.7 x 10(9)/cm(2) using Microtron accelerator at Mangalore University. Surface morphology studies of these crystals are carried out using atomic force microscope. The AFM topographical images of these SHI/electron irradiated single crystals of mixed barium strontium borate are obtained from different frames of the sample taken at different magnifications using atomic force microscope. An attempt is made to explain the surface damage caused due to SHI/electron irradiation using the observed AFM images. (C) 2003 Elsevier Ltd. All rights reserved.