A study of grain size dependent ferroelectric properties of annealed amorphous Bi4Ti3O12

We studied the grain size dependent ferroelectric properties of amorphous B i4Ti3O12 by annealing the sample at 800 degrees C for various times t. The grain size of the sample, measured using a scanning electron microscope, in creased as similar to t(0.25). The grain size dependent ferroelectric prope rties of Bi4Ti3O12 were investigated by measuring a real part of dielectric constant and a D-E hysteresis loop. We found that Bi4Ti3O12 shows two diff erent types of grain size dependence. When the grain size was between 0.08 and 0.36 mu m, the dielectric constant and the polarization increased as th e grain size increased. On the other hand, when the grain size was between 0.36 and 0.47 mu m, the dielectric constant and the polarization decreased as the grain size increased. We explained these observations by the stress effect and the: domain twinning effect, respectively.