Diffuse Phase Transition in Pb₂Sb₃DyTi₅O₁₈Ceramic

Abstract

Polycrystalline sample of Pb 2 Sb 3 DyTi 5 O 18 , a member of tungsten-bronze (TB) family, was prepared using a high temperature solid-state reaction technique. XRD analysis indicated the formation of a single-phase orthorhombic structure. The dielectric studies revealed the diffuse phase transition and the transition temperature found to be at 301 • C. The activation energy was estimated to be 0.62 eV from the temperature variation of dc conductivity. The nature of variation of dc conductivity with temperature suggested NTCR behaviour.

Raman and impedance spectroscopy methods of P 2 O 5 –Li 2 O–Al 2 O 3 glass system doped with MgO

“…The frequency at which merging of (Z′) values for takes place appears to shift towards higher frequency side of the spectrum with rise in concentrations of MgO. The merger of real part of impedance (Z′) in the higher frequency domain suggests release of space charge and a consequent lowering of the barrier properties in the materials[39,40]. The higher impedance value at lower frequency is also an indication of the space charge polarization of the materials[41].…”