Synthesis and characterisation of doped 6H-BaTiO3 ceramics

Hexagonal 6H-BaTiO3 has been stabilised at room temperature according to the formula Ba(Ti1−xMx)O3-δ where M=Mg, Al, Cr, Mn, Fe, Co, Zn, Ga, Ni and In. Solid solution ranges are reported for samples prepared by the mixed oxide route at 1400 °C. Rietveld refinement of Neutron Diffraction data for BaTi0.92Ga0.08O2.96 in the space group P63/mmc shows the presence of oxygen vacancies in the hexagonally close packed layers between face sharing Ti2O9 dimers. All materials are dielectric insulators at room temperature with permittivity values between ∼50–80. Several compositions resonate at microwave frequencies with quality factors (Q.f) between ∼1300–7700 GHz.