Significant dielectric enhancement in 0.3BiFeO3-0.7SrBi2Nb2O9

Significant dielectric enhancement is observed in 0.3BiFeO(3)-0.7SrBi(2)Nb(2)O(9), when a single-phase layered perovskite structure was formed by sintering the mechanically activated oxide composition. The Curie point of xBiFeO(3)-(1-x)SrBi2Nb2O9 was shifted upward with an increase in the BiFeO3 content. 0.3BiFeO(3)-0.7SrBi(2)Nb(2)O(9) exhibits a dielectric constant of 1.84x10(5) at the Curie point of 750 degreesC. The lattice dimensions of xBiFeO(3)-(1-x)SrBi2Nb2O9 decrease slightly with an increase in the content of BiFeO3 over the composition range of x=0-0.2, while 0.3 mol BiFeO3 in SrBi2Nb2O9 led to recovery in the lattice dimensions. The much enhanced dielectric properties observed in 0.3BiFeO(3)-0.7SrBi(2)Nb(2)O(9) are therefore due to the enlarged rattling space for both Nb5+ and in particular for smaller Fe3+. (C) 2001 American Institute of Physics.