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-delta 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 degreesC. Rietveld refinement of Neutron Diffraction data for BaTi0.92Ga0.08O2.96 in the space group P6(3)/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 similar to 50-80. Several compositions resonate at microwave frequencies with quality factors (Q.f) between similar to 1300-7700 GHz. (C) 2003 Elsevier Ltd. All rights reserved.