Department of Physics

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    Li{sub 2}SO{sub 4}−Li{sub 2}O−P{sub 2}O{sub 5} ionic glass dispersed with [Bmim] [PF{sub 6}] ionic liquid: Electrical transport and thermal stability investigations
    (Office of Scientific and Technical Information, 2014) Dalvi, Anshuman
    A fast ionic composite is prepared by dispersion of Ionic liquid [Bmim][PF{sub 6}] in Li{sub 2}SO{sub 4}−Li{sub 2}O−P{sub 2}O{sub 5} glass matrix by mixing and through grinding. Amorphous/glassy nature of the samples is confirmed by X-Ray diffraction (XRD). Surprisingly, the electrical conductivity of the samples is found to be increasing by ∼ 2 orders of magnitude and exhibits typical Arrhenius behavior with low activation energy. DC polarization and impedance spectroscopy measurements suggest that samples are essentially ionic in nature. The conductivity isotherms were also obtained at different temperatures (T < 100 °C) and found to be appreciably stable at least for ∼ 10 days.
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    Magnetic phase transitions in Fe{sub 80-x}Ni{sub x}Cr{sub 20} (14 {<=} x {<=} 30) alloy studied by using {sup 57}Fe Moessbauer spectroscopy
    (ETDE Web, 1999-11) Bandyopadhyay, Debashis
    This paper reports {sup 57}Fe Moessbauer spectroscopic studies of the polycrystalline samples of the substitutionally disordered, isostructural (fcc), ternary alloy system Fe{sub 80-x}Ni{sub x}Cr{sub 20} for x = 30, 26, 19 and 14 in the temperature range of 10-295 K. The data have been analyzed in terms of the magnetic phase transitions occurring in these alloys by examining the temperature dependence of the various Moessbauer parameters like line-width, center shift, resonance area, distribution of hyperfine field, P(H), and the average hyperfine field . An estimate of the magnetic transition temperature T{sub C} is made for the alloys with x = 30 and 26 and these results are compared with those previously obtained by magnetic measurements and neutron diffraction experiments. The data for the second order Doppler shift have been analyzed to estimate the Debye temperature {theta}D for alloys with x = 30 and 26.