Synthesis and DC conductivity studies of multivalent substituted ABO3 perovskite KNN multifunctional ferroelectric materials

Abstract

Lead free piezoelectric samples of ABO3 perovskite structure were prepared, via double sintering method, having composition (K0.5Na0.5)(1-x)Li(x)(Zr0.025Nb0.98) (x =0.0,0.025). In these compounds Li partially replaced K and Na at A site whereas B site was doped with Zr = 0.025 in place of Niobium. Another sample with formula (K0.5(Na0.475Li0.025))(Zr0.025Nb0.98))O3 was also formed where only Na was replaced with Li (0.025), keeping K as (0.5) and Zr/Nb in the same ratio as in previous sample . All the three samples were prepared by using solid state reaction method. Hygroscopic K2CO3 and Na2CO3materials were preheated before using for grinding. All the raw materials were taken in stoichiometric ratio, then ground for eight hours and later calcined at different temperatures and times. Calcined powders were pelletized with dimensions of 10mm diameter and 1 to 1.5 mm thickness. Sintering temperature and duration of sintering were different for different samples. These pellets were used to studythe structure of the samples through XRD. SEM micrographs were taken to observe grain structure and DC conductivity properties of all the samples were studied. From DC conductivity plots, activation energies for conduction were obtained. Results obtained are discussed.