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 ...
Read More
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.
Aditya Jain; Neelam Maikhuri; Rakesh Saroha; Mukul Pastor; A. K. Jha; A. K. Panwar
Abstract
In this investigation, the microstructural and dielectric properties of pure BaTiO3 and vanadium (V 5+ ) substituted on Ba 2+ site (A-site) and Ti 4+ site (B-site) in BaTiO3 ceramic have been studied. The three compositions of BaTiO3 (BT), Ba0.9V0.1TiO3 (BTA) and BaTi0.9V0.1O3 (BTB) were synthesized ...
Read More
In this investigation, the microstructural and dielectric properties of pure BaTiO3 and vanadium (V 5+ ) substituted on Ba 2+ site (A-site) and Ti 4+ site (B-site) in BaTiO3 ceramic have been studied. The three compositions of BaTiO3 (BT), Ba0.9V0.1TiO3 (BTA) and BaTi0.9V0.1O3 (BTB) were synthesized using solid-state reaction route. The XRD analysis of all three compositions has been carried out at room temperature and proper phase formation for BT, BTA and BTB are confirmed. However, compositions BTA and BTB indicate the presence of secondary phases, and it may be due to higher amount of vanadium substitution at A and B sites. Addition of vanadium inhibited the grain growth of BaTiO3 ceramic. Vanadium substitution on A- and B-site have resulted in decrease of Curie temperature as well as dielectric loss compared to pure BT. A more diffused behavior is observed in vanadium substituted samples as compare to pure BT which shows a sharp transition and lower value of diffuseness parameter. Impedance study shows that substitution of vanadium on A- as well as B-site results in decrease of AC conductivity. These properties of vanadium substituted samples can be utilized to reduce the dielectric loss in capacitors and in radio frequency applications.
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 ...
Read More
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.
