EFFECTS OF LANTHANUM DOPING ON THE ELECTRICAL PROPERTIES OF SOL-GEL DERIVED AND MECHANICALLY ACTIVATED Pb۱.۱- X LaX (Zr۰.۵۳Ti۰.۴۷) O۳, NANO POWDERS

Abstract: The PZT-based ceramics with a composition of Pb۱.۱-xLax (Zr۰.۵۳Ti۰.۴۷)O۳, were prepared by conventional mixed oxide followed by mechanical alloying and sol-gel methods in which x was chosen in the range of ۰.۰۲–۰.۰۶. The samples were calcined in the range of ۴۵۰ °C - ۷۵۰ °C for ۴h. The physical and electrical properties of the samples were determined as a function of the calcination temperature. The obtained data from two methods were compared with conventional mixed oxide method. Microstructural and compositional analyses of the samples were carried out using XRD and SEM. Dielectric properties of the samples were measured with an impedance analyzer. The ferroelectric properties of the PZT and PLZT samples were measured using the frequencies applying equipment and d۳۳ tester. The results indicated a complete tetragonal phase prepared from both methods. It was shown that the addition of La and reduction in calcination temperature improved both the dielectric and piezoelectric properties. The dielectric constant tended to increase with doping content, giving the maximum value of about ۲۰۰۰ at ۳ mol% La۳+. In addition, the mechanical coupling factor (Qm) of the doped samples showed a significant decrease. Finally, the value of planar coupling factor (kp) reached the maximum value of ۰.۴۷ at ۱ mol% La۳+.

کلیدواژه ها:

PLZT ، Electrical Properties ، Nanopowder ، Microstructure ، XRD and SEM.