Papers by Author: C. Sanjeeviraja

Abstract: Zircaloy-2, an useful nuclear material is studied here by photoacoustics to correlate with the measurements of X-rays. The microstructure variations observed in X-rays could be explained on the basis of thermal diffusivity measured by photoacoustics technique.

Abstract: The nuclear material, Zircaloy-2 is studied here by photoacoustics and the results are correlated with ultrasonic measurements and metallographic microstructures. Precipitation of hard intermetalics and formation of α-martensite, due to thermal aging are also explained through photoacoustic studies.

Abstract: Alloy D9 is a candidate material for core components of fast breeder reactors. This alloy has been 20% cold worked and thermally aged at 1073 K for different time durations and their thermal properties have been studied using photoacoustic (PA) measurements. The results of the PA measurements have been correlated well with the ultrasonic velocity and hardness measurements.

Abstract: Thin films of pure metals, alloys, semiconductors and organic compounds are indispensable tools in industry, which anticipate and recognize novel functional materials for the development of microelectronics. Thin film technology makes it possible to deposit ultra-thin functional material layers on a base substrate to form many active and passive micro-miniaturized components and devices such as solar cells, radiation sources, sensors, magnetic devices, bolometers, switching devices, photodiodes, digital versatile disk (DVD), flat panel display etc. Thus thin films play a dominant role in modern technology like opto-electronics, microelectronics etc. The study of surfaces and thin films overlaying them has been carried out for many years. But recently, it has become increasingly important in several fields of study. Thin film properties such as optical, electrical and magnetic properties are very much interested in research areas. Thin film properties are strong dependent on the method of deposition, the substrate materials, the substrate temperature, the rate of deposition, the background pressure etc. Specific application in modern technology demand tailor made film properties, for example, high optical reflection / transmission, hardness. adhesion, nonporosity, high mobility of charge carriers / insulating properties and chemical inertness, which are possible with a selection of suitable functional materials and deposition techniques. Various techniques used to deposit thin films and the material properties of MIO and its crystal structure are summarized with our results.

Abstract: New software using VEE Pro was developed to integrate the various components of photoacoustic spectrometer through RS-232 interface and this is the first time such an effort is made not only to integrate but also to automatically acquire the data for depth profile and wave length scanning. The performance and validity was rigorously tested for repeatability and standard error for samples like air, glass and silicon wafer. As an application towards NDE, the thermal parameters obtained from photoacoustics are compared with ultrasonics and discussed.

Abstract: A nanocrystalline tin oxide (SnO2) powders have been prepared by a simple, low-temperature initiated, self-propagating and gas producing by microwave-assisted solution combustion process. The effects of temperature on crystalline phase formation and particle size of nanocrystalline SnO2 and its structure have been investigated. It is observed that heat-treated upto 800°C shows tetragonal phase SnO2. It was observed that the average crystallite size of the annealed SnO2 samples is in the range 9 - 43 nm through controlled heat treatment process. The crystal density of the as-prepared powder is 5.850g cm-3 where as the bulk density is 6.998 g cm−3. The microstructure and morphology were studied by scanning electron microscope (SEM) and HRTEM it is interesting to note that as-prepared SnO2 sample are almost spherical in shape and average agglomerate crystal size of 0.2 – 0.4 μm with increase in calcination temperature, the samples become better morphology than the as-prepared sample. The crystallographic parameters were refined by XRD pattern and Rietveld refinement using TOPAS-3 and Diamond software was used to construct the structural parameters.

Abstract: Thin films continue to become more and more integral to numerous applications in today's advancing technologies. In recent years, thin film science has grown world-wide into a major research area. The importance of coatings and the synthesis of new materials for industry have resulted in a tremendous increase of innovative thin film processing technologies. Thin film properties are strongly dependent on the method of deposition, the substrate temperature, the rate of deposition, the background pressure etc. Hardness, adhesion, non porosity, high mobility of charge carriers / insulating properties and chemical inertness, which are possible with a selection of suitable functional materials and deposition techniques. There are number of different techniques that facilitate the deposition of stable thin films of oxide materials on suitable substrates. Material properties of gallium zinc oxide thin films and all the techniques used to deposit thin films are summarized with an elaborative account along with our results.

Abstract: Thin films have become important for basic studies in physics and in many other fields. The immense interest in basic properties of thin films is due to considerable variations in their properties compared to those of the bulk material. Studies of the optical, electrical and magnetic properties, investigations of structural disorder and phase transition and of various surface phenomena are very much interest in research areas. The results obtained by research on basic studies are useful for the technical application of thin films. Thin films have greater deviations in their behavior corresponding to their original bulk materials. Because of small thickness certain physical features are observed such as optical interference, electronic tunneling through an insulating layer, high resistivity, low temperature coefficient of resistance, increase in optical magnetic fields and optical temperatures of superconductors. Material properties of indium zinc oxide thin films and all the techniques used to deposit thin films are summarized with an elaborative account along with our results.