http://nopr.niscair.res.in/handle/123456789/12586 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/12595 Title: Temperature dependence of antiferroeletric mode frequency, dielectric constant and loss tangent in deuterated squaric acid crystal <br/> <br/>Authors: Upadhyay, Trilok Chandra <br/> <br/>Abstract: By fitting model values of physical quantities for deuterated SQA crystal in theoretically derived expression for AFE mode frequency, dielectric entrant and loss tangent in my earlier paper [<i>Indian J Pure &amp; Appl Phys, </i>47 (2009) 119] temperature dependence of these quantities have been calculated and compared with experimental data of Maier <i>et al., </i><i style="">Phys Status Solidi (b), </i>89 (1978) 578 and Semmingsen, D<i style="">, Acta Chem Scand</i>, 27 (1977) 3961, which show a good agreement. <br/> <br/>Page(s): 633-636 Mon, 29 Aug 2011 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/12594 Title: Specific heat jump and transition temperature <i>T</i>_Cfor La₂_-xBa_xCuO₄, Bi₂Ca_n_-1Sr_nCu_nO_2n+3and Tl₂Ca_n_-1Ba₂Cu_nO_2n+3(2n+4) superconductors <br/> <br/>Authors: Nyawere, P W Otieno; Khanna, KM <br/> <br/>Abstract: The transition temperature <i style="">T</i>_C and the specific heat jump ∆<i style="">C</i>/<i style="">T_C</i> in La₂_-xBa_xCuO_4,Bi₂Ca_n_-1Sr_nCu_nO_2n+4 and Tl₂Ca_n_-1Ba₂Cu_nO_2n+3(2n+4) are calculated using exotic pairing model. These values are calculated at both buckling mode and breathing mode. The values calculated are compared with known experimental values. If ∆ is the gap in the allowed energy states, then the jump in the specific heat is C_S-C_n. These results show that the calculated values of the ratios and <i style="">T</i>_C compare well with experimental values. <br/> <br/>Page(s): 627-632 Mon, 29 Aug 2011 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/12593 Title: Study of electronic and optical properties of Sc-, Y-, Ti-doped transparent conducting oxide <br/> <br/>Authors: Sharma, Yamini; Srivastava, Pankaj <br/> <br/>Abstract: Transparent conducting oxides have important applications as optoelectronic devices. First principles calculations have been performed to study the electronic and optical properties of Sc-, Y- and Ti-doped transparent conducting oxide (TCO) material CdO. The dielectric functions, absorption coefficients and transmittance spectra have been computed to study the effect of doping. The density of states have also been investigated to interpret the calculated optical spectra in terms of inter band transitions. The valence electron charge density is plotted to understand the redistribution of charges on introduction of transition metal ions. The electrical conductivity and Hall coefficient have also been calculated. The calculated band gap for pure CdO which is 0.51 eV increases significantly with doping. The band gaps for Sc-, Y- and Ti- doped CdO are 2.67, 2.83 and 2.53 eV, respectively, which are in good agreement with experimental measurements. <br/> <br/>Page(s): 619-626 Mon, 29 Aug 2011 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/12592 Title: Characterization of cold atomic cloud in a magneto-optical trap <br/> <br/>Authors: Arora, Poonam; Chowdhury, Swatilekha; Agarwal, Ashish; Pant, Kavindra; Gupta, Amitava Sen <br/> <br/>Abstract: The results of characterization of cold cloud of cesium (Cs) atoms trapped in a magneto-optical trap (MOT) have been presented. The MOT is a part of the Physics package of the Cs Fountain Clock being developed at National Physical Laboratory (NPL), India. The number of atoms, size and temperature of the cloud have been measured and calculated. It is also been investigated how the number of trapped atoms changes with the trapping laser’s beam intensity, detuning and magnetic-field gradient of the trap. <br/> <br/>Page(s): 590-595 Mon, 29 Aug 2011 22:58:59 GMT