FETEIRA, Antonio, KEITH, G.M., RAMPLING, M.J., KIRK, C.A., REANEY, I.M., SARMA, K., MC. ALFORD, N. and SINCLAIR, D.C. (2002). Synthesis and characterisation of Ga-doped hexagonal BaTiO3. Crystal Engineering, 5 (3-4), 439-448.Full text not available from this repository.
The hexagonal polymorph of BaTiO3 (P6(3)/mmc) has been stablished at room temperature by partial replacement of Ti by Ga, where BaTi1-yGayO3-y/2 and 0.06less than or equal toyless than or equal to0.125 for samples prepared at 1300degreesC. The unit cell expands with increasing y and Rietveld Refinement of Neutron diffraction data shows that oxygen vacancies occur only in the hexagonal close packed layers between the face-sharing Ti2O9 dimers. Exaggerated grain growth (> 100 mum) Occurs for ceramics processed at greater than or equal to1400degreesC and/or for sintering periods 2 hours. Electrical measurements show the materials to be electrically insulating with room temperature permittivity values of similar to70-80. Dense ceramics (94-97% of the theoretical X-ray density) resonate at microwave frequencies with Q.f values of similar to4000-8000 at similar to5.5 GHz.
|Research Institute, Centre or Group:||Materials and Engineering Research Institute > Structural Materials and Integrity Research Centre > Centre for Corrosion Technology|
|Depositing User:||Hilary Ridgway|
|Date Deposited:||07 Jun 2012 11:44|
|Last Modified:||07 Jun 2012 11:44|
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