  Recent findings of a large electrocaloric (EC) effect in polymeric and
inorganic ferroelectric materials open a potential possibility of development
of solid-state cooling or heating devices of new generation with better energy
efficiency that may be less harmful for the environment. We investigate by
using direct measurements, the temperature and electric field dependence of the
electrocaloric response in Pb1-xLax(ZryTi1-y)1-x/4O3 bulk ceramics (PLZT) with
x=0.06 and 0.12. Here, the properties of the EC response were probed in a part
of the PLZT composition phase diagram with low y=0.40 composition, in which the
EC effect was not previously studied. Measurement results show the existence of
the sizeable EC response in 12/40/60 PLZT sample with the EC temperature change
({\Delta}TEC) of 2.92 K at 430 K and 80 kV/cm. This value exceeds previously
obtained {\Delta}TEC values in relaxor ferroelectric x/65/35 PLZT compositions
and rivaling the best EC response in lead magnesium niobate-lead titanate
ceramics. The electrocaloric responsivity ({\Delta}T/{\Delta}E) value of
0.41x10-6 Km/V determined at a lower electric field of 20 kV/cm and 410 K is
comparable to those observed in other perovskite ferroelectrics.
