Effective pyroelectric response of compositionally graded ferroelectric materials

A thermodynamic theory is used to determine the effective pyroelectric coefficients of polarization graded ferroelectrics, with values in excess of 0.1 mu C/cm(2) degrees C are predicted for various barium strontium titanate thin films. Maximum values closer to 0.4 mu C/cm(2) degrees C are obtained for a 1 mu m thick material-compositionally graded between pure barium titanate and one that has barium to strontium in the ratio of 75:25. (C) 2005 American Institute of Physics.