Theoretical studies on the pyroelectric properties of two component composite ferroelectric thin film

Using a Ginzburg-Landau-Devonshire type model, the pyroelectric property and hysteresis loop are studied for a composite ferroelectric thin film that contains an insertion of a different type of ferroelectric material in parallel connection with the host ferroelectric film material. If these two types of ferroelectric materials are polarized along the same direction, there are two peaks occur in the pyroelectric coefficient vs temperature curve. If the two ferroelectric materials are polarized in opposite directions, one positive and one negative coefficient peaks occur in the temperature dependence of pyroelectric coefficient curve and the hysteresis loop appears to be a quasi-double loop. The effect of the external electric field on the pyroelectric coefficient is also investigated.