Effect of holmium substitution on electrical properties of strontium bismuth tantalate ferroelectric ceramics

The holmium substituted SrBi2−xHoxTa2O9 (x=0.00–2.0) compositions were synthesized by the solid state reaction method. The synthesized specimens were characterized for their structural and electrical properties. X-ray diffractograms reveal single phase layered perovskite structure formation for holmium content up to x≤0.1. The variation of dielectric constant with temperature shows that the Curie temperature (Tc) decreases on increasing the holmium content. The specimen with x=2.0 i.e. the bismuth free specimen, has very low dielectric constant and does not show any appreciable variation with temperature. The dielectric loss reduces significantly with holmium substitution. The ferroelectric property has been observed to improve with Ho substitution. The specimen with x=0.01 exhibits highest remnant polarization (Pr=9.22 μC/cm2) while the bismuth free specimen shows the lowest value of remnant polarization. It is expected that the above ferroelectric materials can be used to replace static (SRAM) and dynamic (DRAM) random access memories with ferroelectric random access memories (FeRAMS).