Origin of large negative electrocaloric effect in antiferroelectric PbZr O 3

We have studied the electrocaloric response of the archetypal antiferroelectric $\mathrm{PbZr}{\mathrm{O}}_{3}$ as a function of voltage and temperature in the vicinity of its antiferroelectric-paraelectric phase transition. Large electrocaloric effects of opposite signs, ranging from an electrocooling of \ensuremath{-}3.5 K to an electroheating of $+5.5\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, were directly measured with an infrared camera. We show by calorimetric and electromechanical measurements that the large negative electrocaloric effect comes from an endothermic antiferroelectric-ferroelectric switching, in contrast to dipole destabilization of the antiparallel lattice, previously proposed as an explanation for the negative electrocaloric effect of antiferroelectrics.