Effective Hamiltonian Methods for Predicting the Electrocaloric Behavior   of BaTiO3
  The perovskite crystal BaTiO3 is modeled using a first-principles based effective Hamiltonian and molecular dynamics simulations are performed to estimate the pyroelectric response. The electrocaloric temperature change, \DeltaT, is calculated for different temperatures and externally applied electric fields. It is found that it is possible to achieve a large \DeltaT, around 5-6 K, for a relatively small electric field gradient, less than 100 kV/cm, if the applied fields have a small absolute magnitude. 
S. P. Beckman, L. F. Wan, Jordan A. Barr, and Takeshi Nishimatsu
cond-mat.mtrl-sci