DIELECTRIC-PROPERTIES OF PB(FE1 2NB1/2)O-3-BASED CERAMICS/

A broad peak above the Curie temperature of lead iron niobate Pb(Fe1/2 Nb1/2)O-3 may be related to interfaces at the grain boundary. The orig in of the anomalous second peak is not clear. The Sr-substituted lead iron niobate Pb1-xSrx(Fe1/2Nb1/2)O-3 ceramics were prepared for the pu rpose of investigating this anomaly. The dielectric anomaly and pyroel ectric current in this system at around 200 degrees C may be explained by the space-charge polarization in the interfaces of the grain bound ary due to ionic valence changes from Fe3+ to Fe2+ in the B-site of th e perovskite structure.