Dielectric properties of Bi4-xLaxTi3O12 (0 ≤ x ≤ 2) ceramics

The dielectric properties of the Bi4-xLax Ti3O12 (0 less than or equal to x less than or equal to 2) ceramics were characterized and discussed together with the P-E relation ( polarization vs. electric field). With increasing x, the P-E relation changed from normal ferroelectric hysteresis loops to pure linear relation, which indicated that La3+ substitution for Bi3+ in Bi4Ti3O12 induced a phase transition from ferroelectric to paraelectric state at ambient temperature. Low loss dielectric ceramics with temperature stable dielectric constant were obtained for x > 1.2 in Bi4-xLax Ti3O12 at 1 MHz. And the loss increased in all the compositions when the ceramics were measured at microwave frequencies.