Patri Tirupathi; Anil Tejomurthula; Nawnit Kumar; Mukul Pastor; R. N. P. Choudhary
Abstract
The polycrystalline sample of Sr-modified Pb(Zr0.5Ti0.5)O3 (i.e. Pb1-xSrx(Zr0.5Ti0.5)O3 (x = 0.05-0.15)) ceramics were synthesized (close to morph-tropic phase boundary) by a cost effective (solid state reaction) method. Detailed investigation of structural phase transition was carried out using room ...
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The polycrystalline sample of Sr-modified Pb(Zr0.5Ti0.5)O3 (i.e. Pb1-xSrx(Zr0.5Ti0.5)O3 (x = 0.05-0.15)) ceramics were synthesized (close to morph-tropic phase boundary) by a cost effective (solid state reaction) method. Detailed investigation of structural phase transition was carried out using room temperature X-ray diffraction data adopting Rietveld refinement technique. The coexistence of two crystal phases (i.e., tetragonal (P4mm) and rhombohedral (R3c) for x = 0.05, and single tetragonal (P4mm) phase for x = 0.1, 0.15) were observed. Elemental analysis, grain shape and size distribution were studied using scanning electron microscope. The decrease in grain size on increasing Sr 2+ concentration was also observed. Detailed analysis of temperature and frequency dependence of dielectric exhibits the increase in dielectric permittivity as function of Sr 2+ concentration at room temperature. Beside this, the greatly reduced Curie (TC) temperature and broadening of dielectric maxima as function of increasing Sr 2+ concentration in PZT was observed. The multiple relaxation processes associated with grain, grain boundaries and interfacial polarization was noted for x=0.05 and x=0.10 to analyze the Nyquist plots. The dominant of grain boundary resistance with increasing in dopent concentration x=0.15 was observed.
Nawnit Kumar; Patri Tirupathi; Bineet Kumar; Mukul Pastor; A. C. Pandey; R. N. P. Choudhary
Abstract
We reports structural, microstructural and dielectric characteristics of Sr 2+ doped PZT (50/50) ceramic. X-ray diffraction reveals that the system exhibit coexistence of two phases (Tetragonal and rhombohedral) at room temperature. Typical relaxor behavior was observed by the dielectric studies and ...
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We reports structural, microstructural and dielectric characteristics of Sr 2+ doped PZT (50/50) ceramic. X-ray diffraction reveals that the system exhibit coexistence of two phases (Tetragonal and rhombohedral) at room temperature. Typical relaxor behavior was observed by the dielectric studies and confirmed by Vogul-Fulcher fitting. The observed relaxor was predicted as existence of nanopolar regions due to short range ordering in presence of oxygen vacancies. The evidence for oxygen vacancies was studied by conductivity and polarization studies. Moreover, at 270 °C one more phase transition is noted which was ascribed to structural phase transition. Present study has scientific significance to distinguish the performance of oxygen vacancies in ferroelectric materials.
Rajiv Ranjan; Nawnit Kumar; Banarji Behera; R. N. P.Choudhary
Abstract
Pb1-xSmx(Zr0.45Ti0.55)1-x/4O3 (PSZT; x = 0.00, 0.03 and 0.06) ceramic samples were prepared by high temperature mixed oxide method. Using complex impedance spectroscopy (CIS) technique, the complex impedance (Z*) and modulus (M*) properties of the materials were analyzed within a wide range of temperature ...
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Pb1-xSmx(Zr0.45Ti0.55)1-x/4O3 (PSZT; x = 0.00, 0.03 and 0.06) ceramic samples were prepared by high temperature mixed oxide method. Using complex impedance spectroscopy (CIS) technique, the complex impedance (Z*) and modulus (M*) properties of the materials were analyzed within a wide range of temperature and frequency. Impedance analysis indicates the presence of mostly bulk resistive (grain) contributions which is found to decrease with the increase in temperature. It suggests about the negative temperature coefficient of resistance (NTCR) type behaviour of the materials. Complex modulus plots exhibit the presence of grain (bulk) as well as grain boundary contributions in the materials and also support their NTCR type behaviour. Both the complex impedance and complex modulus plots confirm the presence of non-Debye type of relaxation in the materials. At higher temperatures, bulk resistance is found to increase with the increase in Sm 3+ concentration in PSZT along with the increase in relaxation phenomenon.
