Browsing by Author "K.K. Bamzai"

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Effect of neodymium doping on structural, electrical and magnetic properties of multiferroic GdMn2O5
(Springer New York LLC, 2017) Deepa Singh; Vandana Gupta; Ranjan K. Singh; K.K. Bamzai
Neodymium doped gadolinium manganate with general composition (Nd0.1Gd0.9Mn2O5) was prepared by co-precipitation method. Microstructural and compositional analysis has been carried out by X-ray diffraction and scanning electron microscopy. The optical studies have been carried out by Raman and FTIR. The electrical properties studied include dielectric constant, dielectric loss, ac conductivity and activation energy in the temperature range 20–400 °C. The shift in the dielectric peak towards higher temperature side with increasing frequency indicates frequency dispersion and suggesting the relaxational behaviour of the material. Frequency dependence of ac conductivity obeys the universal power law. The value of activation energy depends on increase in frequency. The room temperature magnetic behaviour has been analyzed from the magnetic field dependent magnetization curve. The grown material exhibits the paramagnetic behavior at room temperature. © 2017, Springer Science+Business Media New York.
Effect of Ni addition on PNZT tungsten bronze structure
(Springer New York LLC, 2018) Rashmi Gupta; Deepa Singh; Ranjan K. Singh; K.K. Bamzai
Lead niobate zirconate titanate (PNZT) with general formula 0.5PbNb2O6–0.5Pb(ZrxTi1-x)O3 (where x = 0.15, 0.25, 0.35) and lead nickel niobate zirconate titanate (PNNZT) with general formula Pb(NixNb0.5-xZr0.25Ti0.25)O3 (where x = 0.167, 0.250, 0.333) have been prepared by conventional solid state reaction. The phase formation has been studied by X – ray diffraction analysis. Raman investigations have been carried out in the 200–1000 cm−1 wave number range. The structural changes observed in the X – ray diffraction pattern has been further confirmed by Raman analysis. The major changes in the E(1TO), A1(1TO) and E + B1 phonon modes suggest the structural change from cubic to rhombohedral with increase in Ni concentration in PNNZT. The optical band gap has been calculated from UV – Vis absorption spectra. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.