NOPR Collection:http://nopr.niscpr.res.in/handle/123456789/19482026-10-09T15:20:37Z2026-10-09T15:20:37ZStructural and optical studies on texture LiNbO₃ thin film on (0001) sapphireShandilya, SwatiSreenivas, KKatiyar, R SGupta, Vinayhttp://nopr.niscpr.res.in/handle/123456789/19942008-10-11T10:56:37Z2008-08-01T00:00:00ZTitle: Structural and optical studies on texture LiNbO₃ thin film on (0001) sapphire
Authors: Shandilya, Swati; Sreenivas, K; Katiyar, R S; Gupta, Vinay
Abstract: In this work, c-axis oriented lithium niobate thin film has been deposited on Sapphire single crystal substrate by pulse laser deposition. X-ray diffraction showed only reflections corresponding to (006) and (0012) planes of LiNbO₃ on (001) sapphire substrate, indicating that growth of texture LiNbO₃ film on sapphire. The estimated value of c-axis lattice parameter is found to be 1.36 nm and is close to the value reported for LiNbO₃ single crystal. Optical properties of films has been studied using UV-Vis spectrophotometer and the estimated value of refractive index at 640 nm is n = 1.76 nm. A slight dispersion in the refractive index has been observed with photon energy below the interband absorption edge. Raman scattering studies made on prepared sample in the back scattering geometry with incident light normal to the film surface in Z(X+Y,X+Y)Z⁻ configuration indicate the formation of single phase material and free from any type of lattice defects.
Page(s): 355-3572008-08-01T00:00:00ZInfluence of temperature stability on sensing properties of SAW NOx sensorDewan, NamrataHaridas, DivyaShandilya, SwatiSreenivas, KGupta, Vinayhttp://nopr.niscpr.res.in/handle/123456789/19932008-09-16T04:31:19Z2008-08-01T00:00:00ZTitle: Influence of temperature stability on sensing properties of SAW NOx sensor
Authors: Dewan, Namrata; Haridas, Divya; Shandilya, Swati; Sreenivas, K; Gupta, Vinay
Abstract: This paper presents the study on the influence of temperature stability of SAW sensor on the sensing properties for NOx gas. Temperature stable SAW sensor based on 128º YX LiNbO₃ single crystal was developed after integrating with rf sputtered amorphous TeO₂ thin film that act as a temperature compensation over-layer. TeO₂ thin films possessing negative temperature coefficient of delay (TCD) also served as a sensing layer for the detection of NOx gas. Temperature stable SAW devices are essentially desired to avoid the problem of false alarm, besides the enhancement in the sensitivity and reliability.
Page(s): 352-3542008-08-01T00:00:00ZStudies on dielectric properties of a conducting polymer nanocomposite systemMohapatra, Saumya RThakur, Awalendra KChoudhary, R N Phttp://nopr.niscpr.res.in/handle/123456789/19922008-09-16T04:31:12Z2008-08-01T00:00:00ZTitle: Studies on dielectric properties of a conducting polymer nanocomposite system
Authors: Mohapatra, Saumya R; Thakur, Awalendra K; Choudhary, R N P
Abstract: Dielectric analysis of ion conducting solid polymer nanocomposite has been investigated as a function of temperature and frequency. Effect of clay concentration in changing the dielectric relaxation behaviour of polymer salt complex film is clearly visible, observed in terms of changes in polymer chain relaxation and dipolar contribution due to ion pairs. An enhancement in relative permittivity by 2 orders of magnitude has been recorded at room temperature in nanocomposite films controlled predominantly by clay concentration. Almost similar behaviour has been observed after crystalline to amorphous phase transition temperature at T ≥70°C for both polymer salt complex and nanocomposite films irrespective of clay concentration. A lowering of relaxation time, attributed to relaxing dipoles, with clay concentration suggests faster ion dynamics in nanocomposite films.
Page(s): 347-3512008-08-01T00:00:00ZEvaluation of different consolidation methods for nano-materialsKar, SoumenSarma, E SriramSomu, V BKishore, N KSrinivas, Vhttp://nopr.niscpr.res.in/handle/123456789/19912008-09-16T04:31:17Z2008-08-01T00:00:00ZTitle: Evaluation of different consolidation methods for nano-materials
Authors: Kar, Soumen; Sarma, E Sriram; Somu, V B; Kishore, N K; Srinivas, V
Abstract: In the present investigation the effect of high voltage and low frequency current pulses on Ni powder compacts and on alloys like Ni₈₀Si₂₀ or Ni₉₅Si₅ are investigated. The pulse application on ball milled Ni powder compacts and on Ni₈₀Si₂₀ result in a further increase in density. This suggests that the SPS and EDC technique can be used as an alternative method for the sintering of nano-materials and for the densification of nano particles but with the simultaneous application of pressure.
Page(s): 343-3462008-08-01T00:00:00Z