Single crystals and mixed crystals of KH₂PO₄ (KDP) and NH₄H₂PO₄ (ADP) were grown with different dopant concentrations of NH₄H₂PO₄ in KH₂PO₄ in solution by Holden’s rotary crystallizer technique. The effect of additives like Borax (Na₂B₄O₇·10H₂O), seed crystal rotation rate and qualities of the crystals were studied. The half-wave voltages (in longitudinal mode) for KDP mixed with 1% ADP (by weight) were found and hence the unclamped (low frequency) electro-optic coefficients (r₆₃) were calculated for various wavelengths in the visible region of the spectrum. It was noted that the half-wave voltage increases with increase in wavelength and temperature.

Thin films of tellurium of wide range of thicknesses have been deposited by vacuum evaporation and their electrical properties such as electrical resistivity and temperature coefficient of resistance have been measured. The suitability of these films for possible use as strain gauges has been studied and their strain resistivity behaviour is presented. The thermal conductivity of these films have been determined and these results are presented alongwith. An interesting phenomenon has been noticed. In all these effects an extraordinary behaviour is observed at a specific thickness. This smears out with an increase in the thickness of the film. These effects are explained in terms of size effects in thin films.