A series of bismuth layer-structured ferroelectrics

The general formula, Sr(m-3+x)Bi(4-x)Ti(m-x)Ta(x)O(3m+3) (m=2 and 3) is a phase relation between well-known bismuth layer-structured ferroelectrics (BLSF) such as Bi(4)Ti(3)O(12) and SrBi(2)Ta(2)O(9) including a perovskite compound SrTiO(3). The series was discussed to form the layer structure with the numbers m=2 and 3 of layer, where x is the number of Ta ions in the layer structure and 1 less than or equal to x less than or equal to 2 for m=2 and 0 less than or equal to x less than or equal to 2 for m-3. The Curie temperature, T(c), increase as the Sr concentration decreases. From the measurements of D-E hysteresis loops by using a standard Sawyer-Tower circuit, the value of 2P(r) on Sr(0.3)Bi(3.7)Ti(2.7)Ta(0.3)O(12) (m=3) ceramics was the largest (2P(r)=24.6 mu C/cm(2)) in above BLSF series.