抄録
In the paper we would like to present experimental research results of effect of Cr3+ and Ta5+ concentration on structure, microstructure, electric, dielectric, ferroelectric and pyroelectric properties of the ceramic Pb(Zr0.825Ti0.175)O3-x mol% Cr2O3 and the ceramic Pb(Zr0.825Ti0.175)O3-y mol% Ta2O5, where x = 0, 0.5, 0.75, 1, 1.25, 1.50, and 2 mol% and y = 0, 0.5, 1, 1.50, and 2 mol%. Experimental results indicated that Cr3+ and Ta5+ concentrations are of great effect on mentioned above physical properties. Research results of X-ray diffraction diagrams indicated that exist pure perovskite phases with rhombohedral structure in all of ceramic compositions of the systems. From SEM images we can see that rhombohedral grains of 2 μm size closely distributed with small pores. Ceramic densities, dielectric constants, dielectric loss factor are presented with respective values: ρ = 7.48 g/cm3, ε /ε 0 = 343, tan δ= 0.03 for the optimal Cr2O3 concentration of 1.25 mol%. Besides, ceramic densities, dielectric constants, dielectric loss factor are presented with respective values: ρ = 7.51 g/cm3, ε /ε 0 = 307, tan δ= 0.02 for the optimal Ta2O5 concentration of 1 mol%. Cr3+ and Ta5+ concentrations are of very strong effect on structure, microstructure and electric property of the studied systems. Hysteresis loops are of typical rectangular form characterizing ferroelectric materials. Pyroelectric effects are very strong in all compositions of the studied system with maximal pyroelectric coefficients γmax = (0.78-7.72)×10-2 μC/cm2K (for x mol% Cr2O3), γmax = (1.5-24.8)×10-2 μC/cm2K (for y mol% Ta2O5), pyroelectric coefficients at room temperature (306 K) γroom = (0.15-0.96)×10-3μC/cm2K (for x mol% Cr2O3), γroom = (0.05-4.38)×10-3μC/cm2K (for y mol% Ta2O5). [DOI: 10.1380/ejssnt.2012.277]
