The low frequency dielectric dispersion of complex perovskite Pb(Fe 1/2Nb1/2)O3 sintered at different temperatures is carried out as a function of temperature. The sintered samples are annealed in oxygen atmosphere and the effect of annealing on the dielectric properties is investigated. The observed variation in the dielectric dispersion on annealing indicates that the oxidation state of iron plays a significant role in deciding the dielectric properties exhibited by this compound. The results are discussed in conjecture with variation in resistivity and density between the samples. © 2004 Elsevier B.V. All rights reserved.

Venkatachalam Subramanian

Department Of Physics

R. R. Vedantam

Vemuri Rama Krishna Murthy

Annealing

Cooling

Dielectric materials

Dielectric properties

Distillation

Electric resistance

oxidation

Permittivity

Perovskite

Polycrystalline materials

Sintering

Thermal effects

X ray diffraction analysis

COMPLEX PEROVSKITES

Dielectric response

LEAD IRON NIOBATE

Oxidation states

Lead compounds

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Materials Science and Engineering B: Solid-State Materials for Advanced Technology

A comparative study of the properties of two highly ordered lead based complex perovskites Pb(Y b1/2Ta1/2)O3 and Pb(Y b1/2Nb1/2)O3 has been carried out through x-ray diffraction, dielectric and Raman scattering measurements. These two compounds differ significantly in their structure, dielectric response and phonon vibration although the ionic radii and valencies are same for Ta and Nb. The room temperature x-ray diffraction pattern and Raman spectra show that the symmetry of lead ytterbium tantalate is lower than that of lead ytterbium niobate. The Raman spectra of Pb(Y b1/2Ta1/2)O3 also indicates the presence of local distortion in the lattice which may be one of the factors responsible for the existence of a secondary transition. © 2006 Elsevier Ltd. All rights reserved.

Solid State Communications

A comparative study of dielectric and Raman spectroscopy of Pb(Y b1/2Ta1/2)O3 and Pb(Y b1/2Nb1/2)O3

Dielectric dispersion and Raman studies are carried out on the solid solution series (BaxPb1-x)(Yb0.5Nb 0.5)O3 from x = 0.0 to 0.3. The x-ray diffraction analysis indicates that with the substitution of Ba2+, the intensity of the peaks corresponding to antiparallel displacement of Pb2+ decreases and the structure becomes cubic. The low frequency dielectric dispersion studies indicate that the series undergoes a transition from an antiferroelectric to a relaxor ferroelectric with variation of x. Raman spectra of the compositions indicate the presence of a greater number of modes for the compounds with cubic structure (x ≥ 0.2). A new mode at 420 cm-1 is observed for the compounds with Ba2+ substitution. The intensity of this mode increases monotonically with increase in Ba2+ substitution and this has been attributed to the commencement of local distortion. This could be responsible for the appearance and increase in the diffuseness around Tmax, the temperature corresponding to ε′r,max.

Journal of Physics Condensed Matter

Dielectric and Raman studies of (BaxPb1-x)(Yb 0.5Nb0.5)O3

Journal of Physics: Condensed Matter

Structural and dielectric studies of BaFe0.5Nb0.5O3

Journal of the European Ceramic Society

Relationships between Sintering Conditions, Microstructure and Dielectric Properties of Lead Iron Niobate

Ceramics International

Interaction between lead iron niobate/tungstate ceramics and silver/palladium metals

Japanese Journal of Applied Physics

Dielectric Dispersion of the Complex Perovskite OxideBa(Fe1/2Nb1/2)O3at Low Frequencies

Nanostructural-Property Relations in Complex Lead Perovskites

Low frequency dielectric studies on Pb(Fe1/2Nb 1/2)O3

Journal	Data powered by TypesetMaterials Science and Engineering B: Solid-State Materials for Advanced Technology
Publisher	Data powered by TypesetElsevier BV
ISSN	09215107
Open Access	No