Effects of electric field induced polarization on dielectric tunability and pyroelectric coefficient

ABSTRACT Based on the Devonshire theory, a ratio of two thermodynamic parameters, a polarization – temperature coefficient, is found as the crucial for pyroelectric and dielectric tunability effects. Smaller ratio corresponds to larger degree of shift of dielectric peak and larger E-induced polarization. The materials will have higher temperature-stable dielectric tunability suitable for microwave devices. Larger ratio corresponds to larger change of electric hysteresis loop in shape and size with decreasing temperature from the Curie point. The materials will have larger pyroelectric coefficient. An experimental law that pyroelectric coefficient over square root of dielectric constant is a constant is derived.