ELECTROMECHANICAL PROPERTIES OF PIEZOELECTRIC SODIUM ACETYLACETONATE TRANSDUCER

The Tawfik coupling factor is important in evaluating the electromecha nical behaviour of a piezoelectric resonator. It is defined as the squ are root of the ratio of the energy available in mechanical form to th e total input electric energy. It decreases with increasing temperatur e in sodium acetylacetonate resonators. The velocity of the generated ultrasonic wave increases with increasing temperature. This is due to the reversal of some 180 and 90 degree domains to their original orien tations. The increase of the poling field increases the sample polariz ation. This increase of polarization helps the domain wall to vibrate at lower frequencies, giving rise to the observed decrease in sound wa ve velocity of resonators. The decrease of the piezoelectric interacti on among dipoles with rising temperature requires higher frequencies, causing the observed decrease in elastic compliance.