Lily

Tilka Manjhi Bhagalpur University, Bhāgalpur, Bihār, India

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Publications (8)11.94 Total impact

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    ABSTRACT: Polycrystalline sample of (Na0.5Bi0.5)(Zr0.25Ti0.75)O3 was prepared using a high-temperature solid-state reaction technique. XRD analysis indicated the formation of a single-phase orthorhombic structure. AC impedance plots were used as tool to analyse the electrical behaviour of the sample as a function of frequency at different temperature. The AC impedance studies revealed the presence of grain boundary effect, from 350 °C onward. Complex impedance analysis indicated non-Debye type dielectric relaxation. The Nyquist plot showed the negative temperature coefficient of resistance (NTCR) character of (Na0.5Bi0.5)(Zr0.25Ti0.75)O3. AC conductivity data were used to evaluate the density of states at Fermi level and activation energy of the compound. DC electrical and thermal conductivities of grain and grain boundary have been assessed.
    Journal of Alloys and Compounds 04/2008; 453:325-331. · 2.73 Impact Factor
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    Indian Journal of Engineering and Materials Sciences 01/2008; 15:147-151. · 0.36 Impact Factor
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    ABSTRACT: Polycrystalline sample of 2.5 wt% WO3 added (Na1/2Bi1/2)TiO3 was prepared using a high-temperature solid-state reaction method at 1050 ∘C and subsequent sintering at 1090 ∘C in oxygen atmosphere. XRD analysis indicated the formation of a single-phase orthorhombic structure. Dielectric studies revealed the relaxor behaviour. The addition of WO3 to NBT shifts phase transition temperature as well as depolarization temperature to higher side which is desirable for piezoelectric applications. The frequency dependence of the temperature of the permittivity maximum has been modeled using Vogel–Fulcher relation. The dielectric relaxation in the system is found to be analogous to the magnetic relaxation in spin-glass system. The relaxor behaviour in the present system has also been examined through admittance spectroscopy.
    Solid State Communications 10/2007; 144:42-45. · 1.53 Impact Factor
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    ABSTRACT: Polycrystalline sample with (Na0.5Bi0.5)ZrO3 (NBZ) stoichiometry was prepared using a high-temperature solid-state reaction technique. X-ray diffraction (XRD) analyses indicate the formation of a single-phase perovskite-type orthorhombic structure. AC impedance plot is used as tool to analyse the electrical behaviour of the sample as a function of temperature at different frequency. The AC impedance studies revealed the presence of grain boundary effect and evidence of a negative temperature coefficient of resistance (NTCR) character. Pseudo Cole–Cole and complex electric modulus analyses indicated non-Debye-type dielectric relaxation. The AC conductivity obeys the universal power law. The pair approximation type correlated barrier hopping (CBH) model explains the universal behaviour of the s exponent. The apparent activation energy to the conduction process and minimum hopping distance are discussed.
    Journal of Physics and Chemistry of Solids 01/2007; 68(8):1508-1514. · 1.53 Impact Factor
  • Indian Journal of Physics 01/2007; 81(1):103-108. · 1.79 Impact Factor
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    ABSTRACT: Polycrystalline (Na0.5Sb0.5)TiO3 was prepared using a high-temperature solid-state reaction method. An XRD analysis indicated the formation of a single-phase monoclinic structure. Complex impedance studies revealed the presence of grain boundary effects from 300 °C onwards. Also, the dielectric relaxation in the system was found to be of a non-Debye type. The ac conductivity data were used to evaluate the density of states at the Fermi level, the minimum hopping length and activation energy of the compound. The dc electrical and thermal conductivities of grain and grain boundary have been assessed. The correlated barrier hopping model was found to successfully explain the mechanism of charge transport in (Na0.5Sb0.5)TiO3.
    Applied Physics A 01/2007; 88(2):377-383. · 1.69 Impact Factor
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    ABSTRACT: Polycrystalline sample of 2.5 wt% WO3 added (Na1/2Bi1/2)TiO3 was prepared using a high-temperature solid-state reaction method at 1050 ∘C and subsequent sintering at 1090 ∘C in oxygen atmosphere. XRD analysis indicated the formation of a single-phase orthorhombic structure. Dielectric studies revealed the relaxor behaviour. The addition of WO3 to NBT shifts phase transition temperature as well as depolarization temperature to higher side which is desirable for piezoelectric applications. The frequency dependence of the temperature of the permittivity maximum has been modeled using Vogel–Fulcher relation. The dielectric relaxation in the system is found to be analogous to the magnetic relaxation in spin-glass system. The relaxor behaviour in the present system has also been examined through admittance spectroscopy.
    Solid State Communications - SOLID STATE COMMUN. 01/2007; 144(1):42-45.
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    ABSTRACT: Polycrystalline sample of (Na0.5Bi0.5)ZrO3 was prepared using a high-temperature solid-state reaction technique. XRD analysis indicated the formation of a single-phase orthorhombic structure. Dielectric study revealed the diffuse phase transition at 425°C. AC impedance plots were used as tools to analyse the electrical behaviour of the sample as a function of frequency at different temperatures. The ac impedance studies revealed the presence of grain boundary effect at and above 350°C. Complex impedance analysis indicated non-Debye type dielectric relaxation and negative temperature coefficient of resistance (NTCR) character of (Na0.5Bi0.5)ZrO3. AC conductivity data were used to evaluate the density of states at Fermi level and activation energy of the compound. DC electrical and thermal conductivities of grain and grain boundary have been assessed.
    Journal of Materials Science 01/2007; 42(15):6252-6259. · 2.31 Impact Factor