Crystal-Oriented Bi₄Ti₃O₁₂ Ceramics Fabricated by High-Magnetic-Field Method

The effect of powder properties on the degree of crystal orientation of Bi₄Ti₃O₁₂ (BIT) ceramics fabricated by a high-magnetic-field method was investigated. As expected, the degree of orientation of BIT ceramics exhibited little dependence on the crystallinity of the powder, and depended on the particle size of the powder. The degree of orientation increased up to 0.96 when the particle size increased from 0.5 to 1.2 µm. The particle size dependence of the degree of orientation was similar to the relationship between the order parameter and particle size, as derived from Langevin's theory on magnetic alignment. This suggests that the crystal orientation of ceramics fabricated by the high-magnetic-field method can be controlled by selecting the particle size of the powder used.