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The successive phase transitions in a polycrystalline KNO3 sample have been studied using photacoustic and calorimetric techniques. The measured temperature dependence of the photoacoustic amplitude carries signatures of the transitions undergone by the sample. The results indicate that the intermediate ferroelectric phase in KNO3 is only a metastable one. This raises doubts regarding its applicability in fabricating ferroelectric memory devices.

A single-beam photoacoustic phase lag measurement is demonstrated for determining the thermal diffusivity α of solid samples. The method involves measurement of the phase difference of the photoacoustic signal between front and rear surface illuminations at a single chopping frequency with the same light beam. Results on representative samples, with widely different thermal properties, show very good agreement with literature values. Temperature variation of α can also be measured with the setup.

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Plasma generated by the radio frequency ͑rf͒ magnetron sputtering of gallium doped zinc oxide ͑ZnO͒ has been studied using cylindrical Langmuir probe and optical emission spectroscopy. The electron density and electron temperature were calculated for various rf powers at different spatial positions along the propagation direction of the plume. The electron density was found to increase with argon gas pressure whereas electron temperature decreased. The focusing of the plasma due to the magnetic field of the magnetron was observed at 3 cm distance from the target at low rf powers, while shift in the focusing of the plume was observed for high sputtering powers. Plasma potential of the plume was also evaluated at all sputtering conditions and its spatial variations were studied. Optical emission spectra of the plume were recorded at various spatial positions of the plume to get qualitative estimate of species in the plasma at various sputtering conditions. ZnO thin films were deposited on glass substrates placed at 3 and 6 cm distances from the target at different sputtering conditions. X-ray diffraction and scanning electron microscopy studies were carried out to investigate the crystallographic properties and the surface morphology of films deposited at these distances in relation to the plasma parameters.