Ferroelectric material for tuneable microwave application

Abstract

This project consist of synthesising and characterising BaTiO₃, Ba₀.₆Sr₀.₄TiO₃, and SrTiO₃ as ferroelectric material for tuneable microwave application. ZnO were also prepared and characterised as a comparison to the ferroelectric material. The composition were synthesised at 1400⁰C by using solid state reaction method. The prepared powder were confirmed to have single face by analysing the X-ray Diffraction (XRD) pattern. The prepared powder then characterised by using X-ray Diffraction (XRD) and impedance spectroscope. Structural analysis were performed by using GSAS/EXPGUI software. Lattice parameter a, c and volume unit cell obtained shows that BaTiO₃ have the highest value among the three, followed by Ba₀.₆Sr₀.₄TiO₃ and SrTiO₃. BaTiO₃ have tetragonal crystal structure symmetry, but by adding strontium (Sr) to make Ba₀.₆Sr₀.₄TiO₃, it goes structural changes from tetragonal (P m 4 m) to cubic (P m-3 m). SrTiO₃ also shows cubic crystal structure symmetry while ZnO shows hexagonal structure (P 63 m c). By comparing the impedance spectroscope result at room temperature, Ba₀.₆Sr₀.₄TiO₃ shows more stable graph of capacitance and permittivity compared to BaTiO₃ and SrTiO₃. Ba₀.₆Sr₀.₄TiO₃ shows higher capacitance, permittivity and conductivity value.