The application of a new, simple interference technique to the determination of growth concentration gradients of the layer perovskite NH 3(CH 2) 3NH 3CdCl 4

Abstract

A description of a new simple microscopic interference technique is given using a Mach-Zehnder set-up in front of a microscope objective, which enables the direct visualization of concentration gradients and concentration profiles in the solution surrounding a crystal during growth from a temperature and flow controlled bulk solution. The performance and applicability of the technique is compared with the achievements obtained with the help of single and double exposure holograms during direct observation or after reconstruction of single holograms and sandwich holograms. All techniques use coherent lasers as a light source. The performance of these techniques is demonstrated on the example of concentration profiles during growth and dissolution of single crystals up to 10×10×2 mm 3 of the layer perovskite NH 3(CH 2) 3NH 3CdCl 4 from an aqueous solution in an unstirred thermostated cell. The resulting concentration profiles are analysed with the help of the solubility curve and the dependence of the refractive index of the solution on concentration and temperature.