In this work,we intend to perform a detailed study on the crystallization process of PZT 53/47 nanostructured powders by starting out with an amorphous precursor synthesized by a sol-gel based solution.Our interests a...In this work,we intend to perform a detailed study on the crystallization process of PZT 53/47 nanostructured powders by starting out with an amorphous precursor synthesized by a sol-gel based solution.Our interests also lie in the feasibility for controlling the average grain size of the final structure in the submicron range on an ab initio basis.Purposely,Fourier transform infrared spectroscopy（FT-IR）,Raman（Stokes and Anti-Stokes）,X-ray diffraction（XRD） and scanning electron microscopy（SEM） are used to examine the microstructural characteristics based on previously reported differential thermal analysis/thermal gravimetric analysis（DTA/TGA） data.The results show a crystallization temperature of 800℃ to attain pure perovskite phase with excellent morphological quality,average grain size 〈DG〉〈 300 nm and with average crystallite size 〈DC〉〈15 nm.展开更多
The relaxor behavior of PLZT ferroelectric ceramics has been analyzed in a wide frequency and temperature ranges,below and above the temperature for the formation of the so-called polar nano-regions(PNRs).An approxima...The relaxor behavior of PLZT ferroelectric ceramics has been analyzed in a wide frequency and temperature ranges,below and above the temperature for the formation of the so-called polar nano-regions(PNRs).An approximation to the dynamical behavior of the PNRs has been discussed using Cole-Cole’s relaxation model and Jonscher’s Universal Relaxation Law.The analysis considers both the dipolar contribution and those ones associated with DC and AC electric conductivities,this latter not being previously reported in the literature for relaxor materials.The effectiveness of the developed model has been verified from the agreement between the experimental data and the theoretical calculations.This study also offers an indirect method to predict the DC component of the electrical conductivity.展开更多
基金support provided by the CCADET-UNAM Schol-arship Programme
文摘In this work,we intend to perform a detailed study on the crystallization process of PZT 53/47 nanostructured powders by starting out with an amorphous precursor synthesized by a sol-gel based solution.Our interests also lie in the feasibility for controlling the average grain size of the final structure in the submicron range on an ab initio basis.Purposely,Fourier transform infrared spectroscopy（FT-IR）,Raman（Stokes and Anti-Stokes）,X-ray diffraction（XRD） and scanning electron microscopy（SEM） are used to examine the microstructural characteristics based on previously reported differential thermal analysis/thermal gravimetric analysis（DTA/TGA） data.The results show a crystallization temperature of 800℃ to attain pure perovskite phase with excellent morphological quality,average grain size 〈DG〉〈 300 nm and with average crystallite size 〈DC〉〈15 nm.
基金The authors would like to acknowledge the Third World Academy of Sciences(RG/PHYS/LA Nos.99-050,02-225,and 05-043),the Abdus Salam International Centre for Theoretical Physics(ICTP),Trieste,Italy,for financially supporting the Latin-American Network of Ferroelectric Materials(NT-02)and the National Council of Scientific and Technological Development(CNPq)grant 303447/2019-2Minas Gerais Research Foundation(FAPEMIG)grants PPM-00661-16 and APQ-02875-18Coordenacao de Aperfeicoamento de Pessoal de Nível Superior-Brasil(CAPES)-Finance Code 001,and Sao Paulo Research Foundation(FAPESP)grants 06/60013-5 and 2018/24352-7 Brazilian agencies for the financial support.
文摘The relaxor behavior of PLZT ferroelectric ceramics has been analyzed in a wide frequency and temperature ranges,below and above the temperature for the formation of the so-called polar nano-regions(PNRs).An approximation to the dynamical behavior of the PNRs has been discussed using Cole-Cole’s relaxation model and Jonscher’s Universal Relaxation Law.The analysis considers both the dipolar contribution and those ones associated with DC and AC electric conductivities,this latter not being previously reported in the literature for relaxor materials.The effectiveness of the developed model has been verified from the agreement between the experimental data and the theoretical calculations.This study also offers an indirect method to predict the DC component of the electrical conductivity.
