Variation of the pyroelectric and dielectric properties in ceramics of Sr0.3-3y/2LayBa0.7Nb2O6 by defilement with different concentrations of lanthanum

The cationic substitution of 1,3 y 5 % of La3+ in the A sites of the perovskite structure of the Sr0.3-3y/2LayBa0.7Nb2O6 ceramics significantly modifies its dielectric and pyroelectric properties. Experimental measurements of dielectric permittivity as a function of temperature and pyroelectricity as determined by the static method are presented. An improvement in the pyroelectric behavior, in the maximum dielectric permittivity are observed for the compositions with doping up to 3 % of La3+ . For doping of 5 % and above, the above mentioned properties tend to deteriorate apparently due to a solubility limit of the La3+ in the ceramic host. (Author)