The pyroelectric properties of Sr
0.5Ba
0.5Nb
2O
6containing up to 2.0% lanthanum are reported. It is found that the pyroelectric coefficient and the dielectric constant increase while the Curie temperature decreases with the addition of lanthanum in these crystals. High-performance detectors with D* (500,10,1) =

cm(Hz)
1/2/W have been achieved. Methods of improving the response and bandwidth for these detectors are also discussed.