A system for measuring nonlinear dielectric permittivity was set up. The nonlinear dielectric permittivities of thick PT/P[VDF(70)-TrFE(30)] 0-3 ferroelectric composite films have been measured at 1kHz at applied electric field ranging from 1 to 10MV/m.When PT volume fraction ∮ is greater thn 0.3

the dielectric permittivity ε1 of composites shows a distinct dependence on electric field.The Maxwell-Garnett equation is suitable for predication of ε1 when ∮ is less than 0.1.The Yamada model can be usedm to best fit the experimental results

while Bruggeman equation can only be used to predict ε1 at low electric field.The absolute value of the second order dielectric permittivity ε2 increases with increasing PT volume fraction.ε2 of the composites with both the ceramic and copolymer phase being poled (B2) is higher than that of composites with only the ceramic phase being poled (B1).The results show that the magnitude and direction of the remnant polarization of composite films can be determined by measuring ε2. In addition

ε2 is independent of electric field.The third order dielectric permittivity ε3 of composites also shows adependence on electric field.A higher electric field produces a lower ε3.The ε3 value of B1 is always higher than that of B2 for every PT concentration.