STUDY OF THE INFLUENCE OF VARIATIONS IN THE PHASE COMPOSITION ON THE DIELECTRIC PROPERTIES OF FERROELECTRIC CaTiO₃ CERAMICS DOPED WITH Y₂O₃

Abstract

The study of the relationship between the effect of phase composition variation on the dielectric characteristics of ferroelectric ceramics is one of the most important fundamental questions, the answer to which will allow us to determine the potential of using ferroelectrics in microelectronic applications and the creation of alternative energy sources (solid oxide fuel cells). The purpose of this study is to explore the effect of the Y2O3 dopant on the phase formation processes and the properties of the synthesized ferroelectric ceramics of calcium titanate, as well as to establish the connection between the influence of the formation of impurity phases on the change in the dielectric properties of ceramics. According to the data of X-ray phase analysis, it was found that the addition of Y2O3 with a concentration above 0.15 M leads to the formation of an orthorhombic CaY2O4 phase in the ceramic structure, the weight contribution of which increases with the dopant concentration growth. An analysis of the dependence of the specific electrical conductivity (σDC) with varying dopant concentration showed that the maximum value of σDC is achieved at dopant concentrations of 0.05 M, which leads to structural ordering due to the effect of adding yttrium oxide acting as a stabilizer, as well as the formation of impurity donor conductivity in the structure. An analysis of the dependence of the specific electrical conductivity (σDC) from dopant concentration was carried out. It has been established that the maximum value of σDC is achieved at a dopant concentration of 0.05 M. This is explained by structural ordering due to the addition of a stabilizer –  yttrium oxide, as well as the formation of impurity donor conductivity in the synthesized sample. At the same time, the established dependences of the change in dielectric characteristics are in good agreement with the change in the phase composition, and an increase in the concentration of charge carriers due to the introduction of a donor impurity in the form of Y3+ leads to the appearance of volume-charge polarization in ceramics.