Effect of La3+ doping on the polarization of the LSBN ceramic system

The effect of the lanthanum cation as a dopant in the polarization of the Sr0.3-3y/2LayBa0.7Nb2O6 system where y = 0.01, 0.03 and 0.05 is studied. The behavior of the spontaneous polarization and the pyroelectric coefficient obtained by means of the direct integration technique, indicates us that the lanthanum produces an increment of the polarization in the material for values of the composition up to 3%. As the dopant concentration increases toward 5% these properties start to decrease due essentially to a solubility saturation of the substituted ions in the SBN solid solution. This behavior is corroborated through dielectric hysteresis measurements using a modified Sawyer-Tower circuit. (C) 1998 Published by Elsevier Science Ltd