PHYSICAL PROPERTIES OF FERROELECTRIC BI4-xLAxTI3O12 NANO-PARTICLES SYNTHESIZED BY THE CHEMICAL CO-PRECIPITATION METHOD

Bi4 - xLaxTi3O12 (BLT) nano-particles have been synthesised by the chemical co-precipitation method utilizing a polymeric precursor. The particle size decreases from 100 to 40 nm with the increase of La content (x = 0 1) owing to the increase of a reaction temperature. The axial ratio a/b of BLT decreases with the increase of La content reflects a relaxation of structural distortion from its ideal tetragonal structure. A monoclinic to orthorhombic transition occurs at La 0.75. The existence of the soft mode in Raman spectra above x = 0.75 demonstrates a displacive nature of orthorhombic to tetragonal phase transition. No noticeable size effect on physical properties is observed.