Improvement of the dielectric and ferroelectric properties of multiferroic PbO.sub.3 ceramics processed in oxygen atmosphere

Multifunctional materials such as the multiferroic compound Pb(Fe.sub.1/2Nb.sub.1/2)O.sub.3, are of great interest from the academic and technological points of view. However, the occurrence of Fe.sup.2+ and oxygen vacancies originated during the sintering process increase the dielectric loss and el...

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Bibliographic Details
Published inJournal of materials science Vol. 51; no. 13; pp. 6319 - 6330
Main Authors Font, Reynaldo, Raymond-Herrera, Oscar, Mestres, Lourdes, Portelles, Jorge, Fuentes, Juan, Siqueiros, Jesus M
Format Journal Article
LanguageEnglish
Published Springer 01.07.2016
Subjects
Ceramic materials
Ceramics
Comparative analysis
Electric properties
Electrical conductivity
Grain boundaries
Sintering
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Summary:Multifunctional materials such as the multiferroic compound Pb(Fe.sub.1/2Nb.sub.1/2)O.sub.3, are of great interest from the academic and technological points of view. However, the occurrence of Fe.sup.2+ and oxygen vacancies originated during the sintering process increase the dielectric loss and electrical conductivity, detrimental to optimal device performance. Here, a report on the effects of a saturated O.sub.2 atmosphere used during the calcination and sintering stages is presented. A comparative study of structural, morphological, and physical properties with those obtained for samples sintered in air or in its own atmosphere, is presented. The O.sub.2 atmosphere enhances the dielectric constant by ~180 % (with maximum ζ.sub.r of 12700 at T.sub.C = 103 °C and dielectric loss smaller than 0.01 independent of frequency and temperature below 100 kHz and T.sub.C, respectively), the maximum and remanent polarization by ~275 % (P.sub.max from 6.2 to 16.8 µC/cm.sup.2 and P.sub.r from 2.4 to 6.7 µC/cm.sup.2 at 16 kV/cm), and reduces the electrical conductivity by one order of magnitude (from ~1 x 10.sup.-7 to ~3 x 10.sup.-8/Ω cm at 1 kHz at room temperature). Additionally, a pronounced ac positive temperature coefficient of resistivity effect, strongly dependent on frequency and with potential barrier values from 0.2 eV at 1 kHz to 0.71 eV at 500 kHz, is associated with the highly resistive and capacitive behavior of the grain boundary.
ISSN:0022-2461
1573-4803
DOI:10.1007/s10853-016-9928-1