Dielectric properties of B–site charge balanced Dy–doped SrTiO₃ ceramics for energy storage

Trivalent rare earth dysprosium doped strontium titanate ceramics with B–site charge balanced formula of Dy _x Sr_1–x Ti_1–x/4O₃ (DyST, x = 0.01, 0.02, 0.03, and 0.04) were prepared by solid state reaction method. Single phase with cubic perovskite structure was indexed for all DyST ceramics from their x–ray diffraction patterns. Dense microstructures with grain size lower than 5 μm were observed for DyST ceramics using scanning electron microscope. Both high dielectric constant (ε _r = 3300 at 1 kHz) and strong breakdown strength (E _b > 150 kV/cm) were obtained for DyST ceramics with the composition of x = 0.02. Together with good stability of ε _r vs. bias electric fields and low dielectric loss (tanδ < 0.03 at 1 kHz), the DyST ceramics should be very promising for high voltage energy storage capacitors.