Peculiarities of the dielectric properties of ternary 0.5(Y0.1Zr0.9O2) –0.5(0.6SrTiO3 – 0.4BiScO3) ceramic system

Abstract

Ceramic samples of ternary 0.5(Y0.1Zr0.9O2) – 0.5(0.6SrTiO3 – 0.4BiScO3) system consisting of individual Y0.1Zr0.9O2 and 0.6SrTiO3 – 0.4BiScO3 subsystems were synthesized via solid-state processing techniques. By XRD analysis, a coexistence of tetragonal P42/nmc phase related to the Y0.1Zr0.9O2 subsystem, and cubic Pm3m and tetragonal P4mm phases associated with the 0.6SrTiO3 – 0.4BiScO3 subsystem was found. A deviation of real composition from nominal one for both Y0.1Zr0.9O2 and SrTiO3 – BiScO3 subsystems due to Sc substituting for Zr in the Y0.1Zr0.9O2 subsystem and, vice versa, Zr substituting for Sc in the SrTiO3 – BiScO3 subsystem was also observed. Peculiarities of the dielectric properties related to both diffuse ferroelectric phase transition and dielectric relaxation processes were found and analyzed in comparison with the dielectric properties of twocomponent 0.6SrTiO3 – 0.4BiScO3 system. It was found that the diffuse phase transition in ternary system, firstly, shifts to lower temperatures and, secondly, has a less degree of diffuseness as compared to two-component system. Such kind of behavior could be attributed to a difference of ionic radii of ions Zr4+ and Sc3+. Dielectric relaxation processes associated with the O2- ions migration were observed within temperature 500–800 K for both ternary and two-component systems. Two dielectric relaxation processes related to the Y0.1Zr0.9O2 and 0.6SrTiO3 – 0.4BiScO3 subsystems were found in ternary system, whereas one dielectric relaxation process was observed in two-component system. The activation energies for the dielectric relaxation processes were estimated as ~1.3 eV and ~0.9 eV for Y0.1Zr0.9O2 and 0.6SrTiO3 – 0.4BiScO3 subsystems, respectively, for ternary system, and ~0.75 eV for two-component system.