Fabrication of c-axis-oriented apatite-type polycrystalline La10Si6O27 ceramic and its anisotropic oxide ionic conductivity

The c-axis-oriented apatite-type lanthanum silicate, La10Si6O27, ceramic was successfully fabricated by an application of a high magnetic field followed by a sintering process. Degree of an orientation in the La10Si6O27 ceramic sintered at 1700 °C was 48.1% along (00l) on the Lotgering scale. Conductivity of the c-axis-oriented La10Si6O27 ceramic is about 0.5 orders of magnitude higher than that of the non-oriented La10Si6O27 ceramic. The higher conductivity is caused by an orientation of oxide ions in the grains composing the ceramic, which are located along the c-axis and responsible for the ionic conduction.